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Therapeutic applications involving mesenchymal stem cells (MSCs) encounter challenges of attaining therapeutically potent and scaled up number during in-vitro batch culture. Recently, photobiomodulation (PBM) has emerged as a non-pharmacological method for enhancing MSC number, potency, and secretome production. However, the absence of a versatile, non-invasive technique to accurately identify PBM-induced biochemical alterations hinders the clinical translation of the approach. Raman spectroscopy (RS) can be a potential solution to this challenge. In this study, we demonstrate the utility of micro-RS to determine red light (∼660 nm) induced molecular alterations in human adipose tissue derived MSCs (hADMSCs) exposed to three different red light (∼660 nm) fluence; ∼3, 6 and 9 J/cm 2 . While the immediate changes in response to ∼660 nm exposure are subtle, at 6 and 24 h, there is increase in peak intensity of reducedCytochromes c, c1 and b, phenylalanine,CN stretching, CC lipids, OPO stretchingin cells. Maximum increase in intensity of these peaks was observed at ∼6 J/cm 2 . Raman peak at 1585 cm -1 , assigned to stretching vibration (CαCm) asymmetry of reduced Cyt c and sensitive to cellular redox status, shows notable change. Further, the intensity ratio of 1585 cm -1 and 1452 cm -1 , a suggestive Raman biomarker for cell proliferation, is increased in cells exposed to ∼3 &  ∼6 J/cm 2 followed by a decrease in cells exposed to ∼9 J/cm 2 . Furthermore, both micro-RS intensity ratio (1585 cm -1 /1452 cm -1 ) and MTT data on cell viability are in qualitative agreement with each other and show biphasic response to ∼660 nm exposure. While these results suggest the utility of micro-RS for label free assessment of PBM induced changes in hADMSCs, detailed studies on other cell types are necessary to validate the utility of micro-RS in this field., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: The dramatic increase of drug-resistant bacteria necessitates urgent development of platforms to simultaneously detect and inactivate bacteria causing wound infections, but are confronted with various challenges. Delta amino levulinic acid (ALA) induced protoporphyrin IX (PpIX) can be a promising modality for simultaneous bioburden diagnostics and therapeutics. Herein, we report utility of ALA induced protoporphyrin (PpIX) based simultaneous bioburden detection, photoinactivation and therapeutic outcome assessment in methicillin resistant Staphylococcus aureus (MRSA) infected wounds of mice., Methods: MRSA infected wounds treated with 10% ALA were imaged with help of a blue LED (∼405 nm) based, USB powered, hand held device integrated with a modular graphic user interface (GUI). Effect of ALA application time, bacteria load, post bacteria application time points on wound fluorescence studied. PpIX fluorescence observed after excitation with blue LEDs was used to detect bioburden, start red light mediated antimicrobial photodynamic therapy (aPDT), determine aPDT effectiveness and assess selectivity of the approach., Results: ALA-PpIX fluorescence of wound bed discriminates infected from uninfected wounds and detects clinically relevant load. While wound fluorescence pattern changes as a function of ALA incubation and post infection time, intra-wound inhomogeneity in fluorescence correlates with the Gram staining data on presence of biofilms foci. Lack of red fluorescence from wound granulation tissue treated with ALA suggests selectivity of the approach. Further, significant reduction (∼50%) in red fluorescence, quantified using the GUI, relates well with bacteria load reduction observed post topical aPDT., Conclusion: The potential of ALA induced PpIX for simultaneous detection of bioburden, photodynamic inactivation and "florescence-guided aPDT assessment" is demonstrated in MRSA infected wounds of mice., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2023. Published by Elsevier B.V.)

Antimicrobial photodynamic therapy (aPDT) can be a viable option for management of intranasal infections. However, there are light delivery, fluence, and photosensitizer-related challenges. We report in vitro effectiveness of an easily fabricated, low-cost, portable, LED device and a formulation comprising methylene blue (MB) and potassium iodide (KI) for photoinactivation of pathogens of the nasal cavity, namely, methicillin-resistant Staphylococcus aureus, antibiotic-resistant Klebsiella pneumoniae, multi-antibiotic-resistant Pseudomonas aeruginosa, Candida spp., and SARS-CoV-2.In a 96-well plate, microbial suspensions incubated with 0.005% MB alone or MB and KI formulation were exposed to different red light (~ 660 ± 25 nm) fluence using the LED device fitted to each well. Survival loss in bacteria and fungi was quantified using colony-forming unit assay, and SARS-CoV-2 photodamage was assessed by RT-PCR.The results suggest that KI addition to MB leads to KI concentration-dependent potentiation (up to ~ 5 log 10 ) of photoinactivation in bacteria and fungi. aPDT in the presence of 25 or 50 mM KI shows the following photoinactivation trend; Gm + ve bacteria  > Gm - ve bacteria > fungi  > virus. aPDT in the presence of 100 mM KI, using 3- or 5-min red light exposure, results in complete eradication of bacteria or fungi, respectively. For SARS-CoV-2, aPDT using MB-KI leads to a ~ 6.5 increase in cycle threshold value.The results demonstrate the photoinactivation effectiveness of the device and MB-KI formulation, which may be helpful in designing of an optimized protocol for future intranasal photoinactivation studies in clinical settings., (© 2024. The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature.)

With the rise in microbial resistance to traditional antibiotics and disinfectants, there is a pressing need for the development of novel and effective antibacterial agents. Two major approaches being adopted worldwide to overcome antimicrobial resistance are the use of plant leaf extracts and metallic nanoparticles (NPs). However, there are no reports on the antibacterial potential of NPs coated with plant extracts, which may lead to novel ways of treating infections. This study presents an innovative approach to engineer antibacterial NPs by leveraging the inherent antibacterial properties of zinc oxide NPs (ZnO NPs) in combination with Azadirachta indica ( AI ) leaf extract, resulting in enhanced antibacterial efficacy. ZnO NPs were synthesised by the precipitation method and subsequently coated with AI leaf extract to produce ZnO- AI nanocore-shell structures. The structural and morphological characteristics of the bare and leaf extract coated ZnO NPs were analysed by x-ray diffraction and field emission scanning electron microscopy, respectively. The presence of an AI leaf extract coating on ZnO NPs and subsequent formation of ZnO- AI nanocore-shell structures was verified through Fourier transform infrared spectroscopy and photoluminescence techniques. The antibacterial efficacy of both ZnO NPs and ZnO- AI nanocore-shell particles was evaluated against methicillin-resistant Staphylococcus aureus using a zone of inhibition assay. The results showed an NP concentration-dependent increase in the diameter of the inhibition zone, with ZnO- AI nanocore-shell particles exhibiting superior antibacterial properties, owing to the combined effect of ZnO NPs and the poly phenols present in AI leaf extract. These findings suggest that ZnO- AI nanocore-shell structures hold promise for the development of novel antibacterial creams and hydrogels for various biomedical applications., (© 2024 IOP Publishing Ltd.)

Antimicrobial wound dressings play a crucial role in treatment of wound infections. However, existing commercial options fall short due to antibiotic resistance and the limited spectrum of activity of newly emerging antimicrobials against bacteria that are frequently encountered in wound infections. Antimicrobial photodynamic therapy (aPDT) is very promising alternative therapeutic approach against antibiotic resistant microbes such as methicillin resistant Staphylococcus aureus (MRSA) . However, delivery of the photosensitizer (PS) homogeneously to the wound site is a challenge. Though polymeric wound dressings based on synthetic and biopolymers are being explored for aPDT, there is paucity of data regarding their in vivo efficacy. Moreover, there are no studies on use of PS loaded, pluoronic (PL) and pectin (PC) based films for aPDT. We report development of a polymeric film for potential use in aPDT. The film was prepared using PL and PC via solvent casting approach and impregnated with methylene blue (MB) for photodynamic inactivation of MRSA in vitro and in vivo . Atomic force microscopic imaging of the films yielded vivid pictures of surface topography, with rough surfaces, pores, and furrows. The PL:PC ratio (2:3) was optimized that would result in an intact film but exhibit rapid release of MB in time scale suitable for aPDT. The film showed good antibacterial activity against planktonic suspension, biofilm of MRSA upon exposure to red light. Investigations on MRSA infected excisional wounds of mice reveal that topical application of MB loaded film for 30 min followed by red light exposure for 5 min (fluence; ∼30 J cm -2 ) or 10 min (fluence; ∼60 J cm -2 ) reduces ∼80% or ∼92% of bioburden, respectively. Importantly, the film elicits no significant cytotoxicity against keratinocytes and human adipose derived mesenchymal stem cells. Taken together, our data demonstrate that PS-loaded PL-PC based films are a promising new tool for treatment of MRSA infected wounds., (© 2024 IOP Publishing Ltd.)

Strontium sulphate (SrSO 4 ) is a defect-based photoluminescence material, generally used in thermoluminescence applications, and has been studied for infrared (IR) stimulated visible emission. The SrSO 4 particles were synthesized using a precipitation method. The orthorhombic phase of SrSO 4 was confirmed from the X-ray diffraction pattern and the formation of micron-sized particles was authenticated from field emission scanning electron micrographs. The elemental composition of oxygen and strontium was determined using energy-dispersive X-ray analysis measurement that confirmed the presence of V O • • and V Sr ' ' intrinsic defects in the material. Photoluminescence investigations showed the presence of various defect bands in the band gap giving rise to intrinsic luminescence in SrSO 4 . The emission in the visible region was attributed to the defect band arising due to V O • • . Photoluminescence lifetime measurement confirmed the presence of stable defect states with a lifetime in microseconds. The SrSO 4 sample was tested using IR lasers and a red-orange emission spot was observed from the powder sample when excited with IR lasers. The underlying principle for IR-to-visible conversion in the material is a defect-mediated phenomenon that has been described through the energy level diagram of the material., (© 2023 John Wiley & Sons Ltd.)

Lithium has been the treatment of choice for patients with bipolar disorder. However, lithium overdose happens more frequently since it has a very narrow therapeutic range in blood, necessitating investigation of its adverse effects on blood cells. The possible changes that lithium exposure may have on functional and morphological characteristics of human red blood cells (RBCs) have been studied ex vivo using single-cell Raman spectroscopy, optical trapping, and membrane fluorescent probe. The Raman spectroscopy was performed with excitation at 532 nm light, which also results in simultaneous photoreduction of intracellular hemoglobin (Hb). The level of photoreduction of lithium-exposed RBCs was observed to decline with lithium concentration, indicating irreversible oxygenation of intracellular Hb from lithium exposure. The lithium exposure may also have an effect on RBC membrane, which was investigated via optical stretching in a laser trap and the results suggest lower membrane fluidity for the lithium-exposed RBCs. The membrane fluidity of RBCs was further studied using the Prodan generalized polarization method and the results verify the reduction of membrane fluidity upon lithium exposure., (© 2023. European Biophysical Societies' Association.)

Titanium dioxide (TiO 2 ) photocatalyst has gained constant interest in the treatment of wastewater because of its greater stability, lower cost, low-toxicity, high efficiency, and more reactivity under UV radiation. On the other hand, Graphene oxide (GO) possesses high electron mobility, and therefore when GO is combined with TiO 2, the photocatalytic activity of TiO 2 is increased. In this study, nano-composite was synthesized in a hydrothermal reactor using two types of TiO 2 nanoparticles (TiO 2 consisting of a mixture of rutile and anatase phase (Type 1) and bioreduced TiO 2 (Type 2)) and the efficiency of both the TiO 2 -GO nanocomposite to remove the drug Carbamazepine (CBZ) was investigated. The TiO 2 -GO nanocomposite with the Type 1 TiO 2 exhibited greater efficiency hence further studies were conducted with that composite. The efficiency of TiO 2 -GO nanocomposite for the purpose of removing CBZ were investigated in presence of different types of incident radiation like Solar radiation, white light and three type of Ultraviolet radiation (A, B, C). The removal of the drug by TiO 2 -GO composite has been optimized using response surface methodology and artificial neural network. From this study, the maximum reduction was observed was 91.2% and whereas in case of the RSM optimization study the maximum removal that was observed was 91.7%. The validation of the RSM model was done using the mathematical analysis of the model equation of RSM. Different kinetics models was also analyzed using the experimental data and it was observed that it followed pseudo-second-order kinetics. The optimization using ANN also showed a close interaction with the experimental results., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)