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Epstein-Barr virus (EBV) infection is a global health concern infecting over 90% of the population. However, there is no currently available vaccine. EBV primarily infects B cells, where the major glycoprotein 350 (gp350) is the main target of neutralizing antibodies. Given the advancement of nanoparticle vaccines, we describe rationally designed vaccine modalities presenting 60 copies of gp350 on self-assembled nanoparticles in a repetitive array. In a mouse model, gp350s on lumazine synthase (LS) and I3-01 adjuvanted with MF59 or aluminum hydroxide (Alhydrogel) elicited over 65- to 133-fold higher neutralizing antibody titers than the corresponding gp350 monomer to EBV. Furthermore, immunization with gp350D 123 -LS and gp350D 123 -I3-01 vaccine induced a Th2-biased response. For the nonhuman primate model, gp350D 123 -LS in MF59 elicited higher titers of total IgG and neutralizing antibodies than the monomeric gp350D 123 . Overall, these results support gp350D 123 -based nanoparticle vaccine design as a promising vaccine candidate for potent protection against EBV infection.

Flexible pressure sensors have attracted intense attention because of their widespread applications in electronic skin, human-machine interfaces, and healthcare monitoring. Conductive porous structures are always utilized as active layers to improve the sensor sensitivities. However, flexible pressure sensors derived from traditional foaming techniques have limited structure designability. Besides, random pore distribution causes difference in structure and signal repeatability between different samples even in one batch, therefore limiting the batch production capabilities. Herein, we introduce a structure designable lattice structure pressure sensor (LPS) produced by bottom-up digital light processing (DLP) 3D printing technique, which is capable of efficiently producing 55 high fidelity lattice structure models in 30 min. The LPS shows high sensitivity (1.02 kPa -1 ) with superior linearity over a wide pressure range (0.7 Pa to 160 kPa). By adjusting the design parameters such as lattice type and layer thickness, the electrical sensitivities and mechanical properties of LPS can be accurately controlled. In addition, the LPS endures up to 60000 compression cycles (at 10 kPa) without any obvious electrical signal degradation. This benefits from the firm carbon nanotubes (CNTs) coating derived from high-energy ultrasonic probe and the subsequent thermal curing process of UV-heat dual-curing photocurable resin. For practical applications, the LPS is used for real time pulse monitoring, voice recognition and Morse code communication. Furthermore, the LPS is also integrated to make a flexible 4 × 4 sensor arrays for detecting spatial pressure distribution and a flexible insole for foot pressure monitoring.

The coronavirus disease pandemic of 2019 (COVID-19) caused by the novel SARS-CoV-2 coronavirus resulted in economic losses and threatened human health worldwide. The pandemic highlights an urgent need for a stable, easily produced, and effective vaccine. SARS-CoV-2 uses the spike protein receptor-binding domain (RBD) to bind its cognate receptor, angiotensin-converting enzyme 2 (ACE2), and initiate membrane fusion. Thus, the RBD is an ideal target for vaccine development. In this study, we designed three different RBD-conjugated nanoparticle vaccine candidates, namely, RBD-Ferritin (24-mer), RBD-mi3 (60-mer), and RBD-I53-50 (120-mer), via covalent conjugation using the SpyTag-SpyCatcher system. When mice were immunized with the RBD-conjugated nanoparticles (NPs) in conjunction with the AddaVax or Sigma Adjuvant System, the resulting antisera exhibited 8- to 120-fold greater neutralizing activity against both a pseudovirus and the authentic virus than those of mice immunized with monomeric RBD. Most importantly, sera from mice immunized with RBD-conjugated NPs more efficiently blocked the binding of RBD to ACE2 in vitro , further corroborating the promising immunization effect. Additionally, the vaccine has distinct advantages in terms of a relatively simple scale-up and flexible assembly. These results illustrate that the SARS-CoV-2 RBD-conjugated nanoparticles developed in this study are a competitive vaccine candidate and that the carrier nanoparticles could be adopted as a universal platform for a future vaccine development.

To enhance signal acquisition stability and diminish background interference for conventional flow bead-based fluorescence detection methods, we demonstrate here an exceptional microfluidic chip assisted platform by integrating near-infrared optical tweezers with upconversion luminescence encoding. For the former, a single 980 nm laser is employed to perform optical trapping and concurrently excite upconversion luminescence, avoiding the fluctuation of the signals and the complexity of the apparatus. By virtue of the favorable optical properties of upconversion nanoparticles (UCNPs), the latter is carried out by employing two-color UCNPs (Er-UCNPs and Tm-UCNPs) with negligible spectral overlaps. With the assistance of the double key techniques, we fabricated complex microbeads referred to a UCNPs-miRNAs-microbead sandwich construct by a one-step nucleic acid hybridization process and then obtained uniform terrace peaks for the automatic and simultaneous quantitative determination of miRNA-205 and miRNA-21 sequences with a detection limit of pM level on the basis of a special home-built flow bead platform. Furthermore, the technique was successfully applied for analyzing complex biological samples such as cell lysates and human tissue lysates, holding certain potential for disease diagnosis. In addition, it is expected that the flow platform can be utilized to investigate many other biomolecules of single cells and to allow analysis of particle heterogeneity in biological fluid by means of optical tweezers.

Although plentiful advanced fluorescence sensors have achieved to analyze microRNAs (miRNAs) in living cells, the prerequisite relating to nucleic acids specific recognition based sensing principle compels them lack favorable accurancy and stability in such complicated biological mediums. Here, we make a double breakthrough for the two challenges by combining a near-infrared (NIR) light powering process with a DNA tetrahedron (DNAT)-based protection concept. In this sensing system, a special nanomachine is first engineered by conjugating a core-shell-structured upconversion nanoparticle capable of highly converting 808 nm NIR photons into ultraviolet ones with self-assembling DNATs. The newly developed nanostructure not only prevents the sensing pathway from triggering during the intracellular delivery as well as reducing the adverse thermal effect for cell viability but also significantly enhances the enzyme resistance to avoid degradation to produce false signals. Furthermore, a fluorescence resonance energy transfer sensing strategy is rationally designed on this nanomachine. Upon using the powering light to excite the upconversion luminescence to activate the nanomachine in living cells, it can stably trace the precise level changes of miRNA-21 sequences at the reaching position with an "off-on" mode of fluorescence outputs.

We demonstrate an effective approach to realize active and real-time temperature monitoring around the gold nanobipyramids (AuNBPs)-labeled cancer cell under 808 nm laser irradiation by combining optical tweezers and temperature-sensitive upconversion microparticles (UCMPs). On the one hand, the aptamer-modified AuNBPs that absorb laser at 808 nm not only act as an excellent photothermal reagent but also accurately and specifically bind the target cancer cells. On the other hand, the single optically trapped NaYF 4 :Yb 3+ , Er 3+ UCMPs with a 980 nm laser exhibit temperature-dependent luminescence properties, where the intensity ratio of emission 525 and 547 nm varies with the ambient temperature. Therefore, real-time temperature variation monitoring is performed by 3D manipulation of the trapped single UCMP to control its distance from the AuNBPs-labeled cancer cell while being photothermally killed. The results show distance-related thermal propagation because the temperature increase reaches as high as 10 °C at a distance of 5 μm from the cell, whereas the temperature difference drops rapidly to 5 °C when this distance increases to 15 μm. This approach shows that the photothermal conversion from AuNBPs is sufficient to kill the cancer cells, and the temperature increase can be controlled within the micrometer level at a certain period of time. Overall, we present a micrometer-size thermometer platform and provide an innovative strategy to measure temperature at the micrometer level during photothermal killing of cancer cells.

Herein, a conceptual approach for significantly enhancing a bead-supported assay is proposed. For the fluorescence imaging technology, optical tweezers are introduced to overcome the fluid viscosity interference and immobilize a single tested bead at the laser focus to guarantee a fairly precise imaging condition. For the selection of fluorescent materials and the signal acquisition means, a type of innovative luminescence confined upconversion nanoparticle with a unique sandwich structure is specially designed to act as an efficient energy donor to trigger the luminescent resonance energy transfer (LRET) process. By further combining the double breakthrough with a molecular beacon model, the newly developed detection strategy allows for achieving a pretty high LRET ratio (≈ 88%) to FAM molecules and offering sound assay performance toward miRNA analysis with a detection limit as low as the sub-fM level, and is capable of well identifying single-base mismatching. Besides, this approach not only is able to accurately qualify the low-abundance targets from as few as 30 cancer cells but also can be employed as a valid cancer early warning tool for performing liquid biopsy.

Establishment of a stable analytical methodology with high-quality results is an urgent need for screening cancer biomarkers in early diagnosis of cancer. In this study, we incorporate holographic optical tweezers with upconversion luminescence encoding to design an imageable suspension array and apply it to conduct the detection of two liver cancer related biomarkers, carcinoembryonic antigen and alpha fetal protein. This bead-based assay is actualized by forming a bead array with holographic optical tweezers and synchronously exciting the upconversion luminescence of corresponding trapped complex beads fabricated with a simple one-step sandwich immunological recognition. Owing to the fact that these flowing beads are stably trapped in the focal plane of the objective lens which tightly converges the array of the laser beams by splitting a 980 nm beam using a diffraction optical element, a fairly stable excitation condition is achieved to provide reliable assay results. By further taking advantage of the eminent encoding capability of upconversion nanoparticles and the extremely low background signals of anti-Stokes luminescence, the two targets are well-identified and simultaneously detected with quite sound sensitivity and specificity. Moreover, the potential on-demand clinical application is presented by employing this approach to respond the targets toward complex matrices such as serum and tissue samples, offering a new alternative for cancer diagnosis technology.

By functionalization of the achiral carboxylate-based pyridine-N ligand 2,2'-bipyridine-3,3'-dicarboxylate (H 2 bpda) with N-oxide groups, the axially chiral ligand 2,2'-bipyridine-3,3'-dicarboxylate 1,1'-dioxide (H 2 bpdado) has been obtained. On the basis of H 2 bpdado and auxiliary N-donor ligands, two isostructural 3D dynamic porous Cu(II) metal-organic frameworks (MOFs), {[Cu 0.5 (bpdado) 0.5 (L) 0.5 ]·3H 2 O} n (L = 1,2-bis(4-pyridyl)ethane (bpa), trans-1,2-bis(4-pyridyl)ethene (bpe) for 1 and 2, respectively), have been synthesized, which contain N-oxide "open donor sites" (ODSs) and carboxyl sites on the pore surfaces. The modification of pyridine-N into the N-oxide group not only transforms the nonporous structure into a porous framework but also endows the N-oxide group with unique charge-separated plus electron-rich character, which may provide an enhanced affinity toward CO 2 molecules. Interestingly, both 1 and 2 present reversible structural transformation upon dehydration and rehydration. The adsorption properties of 1 and 2 have been investigated by N 2 , H 2 , CH 4 , and CO 2 gases, and they reveal evident adsorption for CO 2 and CH 4 . Both MOFs have high CO 2 uptake, CO 2 sorption affinity, and sorption selectivities of CO 2 over CH 4 and N 2 . Remarkably, 1' and 2' exhibit intriguingly comparable temperature-dependent CO 2 sorption behaviors that can probably be attributed to the difference in bpa and bpe. First, at 195 K, 1' and 2' exhibit stepwise adsorption and hysteretic desorption behavior for CO 2 , but in the second step, the isotherms of 2' display a starting pressure greater than that of 1'. Then, at 298 K, their CO 2 isotherms all show nonclassical type I adsorption, while peculiarly, at 273 K, the CO 2 isotherm of 1' still exhibits uncommon stepwise adsorption but that of 2' does not. Thus, these temperature-dependent CO 2 sorption behaviors indicate that there exist different threshold temperatures and pressures of channel expansion for 1' and 2'.

As an emerging fascinating fluorescent nanomaterial, carbon nanodots (CDs) have attracted much attention owing of their unique properties such as small size, antiphotobleaching, and biocompatibility. However, its use in biomedical analysis is limited because of its low quantum yield. Herein, we constructed a dual amplification fluorescence sensor by incorporating immunohybridization chain reaction (immuno-HCR) and metal-enhanced fluorescence (MEF) of CDs for the detection of alpha fetal protein (AFP). The immunoplasmonic slide and detection antibodies-conjugated oligonucleotide initiator are served to capture and probe AFP molecules, respectively. Then, CD-tagged hairpin nucleic acids were introduced to trigger the HCR, in which the hairpin nucleic acid and oligonucleotide initiator are complementary. The interaction between CDs and the gold nanoisland film greatly improves the radiative decay rate, increases the quantum yield, and enhances the fluorescence emission of the CDs. Furthermore, the HCR provides secondary amplification of fluorescence intensity. Therefore, the MEF-capable immunohybridization reactions provide obvious advantages and result in exceptional sensitivity. In addition, the sandwich immunoassay method offers high specificity. The results show a wide linearity between the fluorescence intensity and AFP concentration over 5 orders of magnitude (0.0005-5 ng/mL), and the detection limit reaches as low as 94.3 fg/mL. This method offers advantages of high sensitivity and reliability, wide detection range, and versatile plasmonic chips, thus presenting an alternative for the technologies in biomedical analysis and clinical applications.

We present an analytical platform by combining near-infrared optical tweezers with two-photon excitation for fluorescence detection of H5N1 virus gene sequences. A heterogeneous enrichment strategy, which involved polystyrene (PS) microsphere and quantum dots (QDs), was adopted. The final hybrid-conjugate microspheres were prepared by a facile one-step hybridization procedure by using PS microspheres capturing target DNA and QDs tagging, respectively. Quantitative detection was achieved by the optical tweezers setup with a low-cost 1064 nm nanosecond pulse laser for both optical trapping and two-photon excitation for the same hybrid-conjugate microsphere. The detection limits for both neuraminidase (NA) gene sequences and hemagglutinin (HA) gene sequences are 16-19 pM with good selectivity for one-base mismatch, which is approximately 1 order of magnitude lower than the most existing fluorescence-based analysis method. Besides, because of the fact that only signal from the trapped particle is detected upon two-photon excitation, this approach showed extremely low background in fluorescence detection and was successfully applied to directly detect target DNA in human whole serum without any separation steps and the corresponding results are very close to that in buffer solution, indicating the strong anti-interference ability of this method. Therefore, it can be expected to be an emerging alternative for straightforward detecting target species in complex samples with a simple procedure and high-throughput.

The catalytic asymmetric addition of phenylacetylene to aromatic ketones is reported. The catalyst, generated from commercially available Cinchona alkaloids and industrially available triethylaluminum, gives the expected tertiary alcohols with good enantiomeric excess (70-89%) and yields (60-83%). No previous case has been reported successfully using triethylaluminum as a Lewis acid in the asymmetric alkynylation of carbonylic derivatives, and thus we provide a new method to obtain optically active tertiary propargyl alcohols.