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Protease inhibition is the intended mechanism of action for drugs across a broad range of diseases: cancer, cardiovascular and stroke, diabetes mellitus, macular degeneration and Alzheimer’s. Treatment for fungal and multiple viral infections, including Sars-Cov-2, also relies upon inhibition of pathogen-specific proteases. This work examines the non-therapeutic proteolytic activity of one such drug, nelfinavir (tradename VIRACEPT™), approved as an inhibitor of HIV protease, the largest, “biotech launch” in history at the time of its introduction. Methods are described in the companion manuscript [Leonard et al. (2022), 4open 5, 11]. These methods are not only suitable for examination of on-target activity but also of off-target activity. Herein, it is demonstrated that nelfinavir is active both as an inhibitor and as a promoter of proteolysis of key blood proteins. Observations are readily connected to known drug induction of acute pancreatitis and attendant hypoalbuminemia. The benefits of expanding molecular-level, early-stage, off-target/off-substrate activity drug candidate evaluation become apparent. Finally, the reality of drug-induced disease places new demands on existing clinical procedures, namely that side effects be approached as symptoms of an induced disease.

Recently the treatment PAXLOVID™ (nirmatrelvir co-packaged with ritonavir) was authorized for use as a treatment for COVID-19. The presumed mechanism of action of the treatment, an inhibitor of a Sars-Cov-2 “3CL” protease, continues decades-long interest in viral protease inhibition in the fight against pathogenic viruses (e.g., HIV protease inhibitors). Proteolysis assay methods vary widely, roughly bounded by interrogation of basic biochemistry and high-throughput, early-stage drug screening. Reported here are methods that provide unique and biologically relevant characterization of proteolysis and protease inhibition. A companion report provides evidence that these methods show promise for drug and basic biological discovery, especially for early detection of potential side effects. Electron spin resonance spectroscopy and spin labeling (ESRSL) of whole proteins are leveraged to monitor reactants and products of whole-protein digestion through differentiation of angular mobility of those products and reactants. These proof-of-concept data demonstrate consistency with prior art for all possible combinations of four proteases, two whole-protein substrates and three inhibitors. Thus, ESRSL is shown to uniquely and widely interrogate proteolysis of natural, whole-protein, substrates insuring the biological relevance of results.

We report a new method, microfluidic flow-flash, for measuring protein reaction kinetics. The method couples a microscope imaging detection system with a microfluidic flow cell to reduce data acquisition times and sample consumption. This combination allows for the simultaneous collection of spectral and temporal information. The microfluidic flow cell design utilizes three-dimensional sheath flow to reduce sample dispersion and minimize sample consumption. The ability to alter the flow rates in the microfluidic flow cells allows a variety of time scales to be studied with submillisecond time resolution. The imaging detection system can be coupled with several spectroscopic probes including fluorescence and UV/ visible absorbance spectroscopy. Here, we utilize the microfluidic flow-flash method to probe the kinetics of CO recombination or [O.sub.2] binding to myogiobin after the laser-induced photolysis of CO from myogiobin by UV/visible absorbance spectral imaging.

High-resolution, conformable phase masks provide a means to fabricate, in an experimentally simple manner, classes of 3D nanostructures that are technologically important but difficult to generate in other ways. In this approach, light passing through a phase mask that has features of relief comparable in dimension to the wavelength generates a 3D distribution of intensity that exposes a photopolymer film throughout its thickness. Developing this polymer yields a structure in the geometry of the intensity distribution, with feature sizes as small as 50 nm. Rigorous coupled-wave analysis reveals the fundamental aspects of the optics associated with this method; a broad-range 3D nanostructures patterned with it demonstrates its technical capabilities. A nanoporous filter element built inside a microfluidic channel represents one example of the many types of functional devices that can be constructed.

This paper demonstrates that the pattern of silver particles embedded in the gelatin matrix of exposed and developed silver halide-based photographic film can serve as a template in a broadly applicable method for the microfabrication of metallic microstructures. In this method, a CAD file is reproduced in the photographic film by exposure and developing. The resulting pattern of discontinuous silver grains is augmented and made electrically continuous by electroless deposition of silver, and the electrically continuous structure is then used as the cathode for electrochemical deposition of an additional layer of the same or different metal. The overall process can be completed within 2 h, starting from a CAD file, and can generate electrically continuous structures with the smallest dimension in the plane of the film of approximately 30 (mu)m. Structures with aspect ratio of up to 5 can also be obtained by using the metallic structures as photomasks in photolithography using SU-8 photoresist on the top of the electroplated pattern and exposed from the bottom, followed by development and electroplating through the patterned photoresist. This method of fabrication uses readily available equipment and makes it possible to develop prototypes of a wide variety of metallic structures and devices. The resulting structures-either supported on the film backing or freed from it-are appropriate for use as passive, structural materials such as wire frames or meshes and can also be used in microfluidic, microanalytical, and microelectromechanical systems.

This paper describes the use of laminar flow of liquids in capillary systems to pattern the cell culture substrate, to perform patterned cell deposition, and to pattern the cell culture media. We demonstrate the patterning of the cell culture substrate with different proteins, the patterning of different types of cells adjacent to each other, the patterned delivery of chemicals to adhered cells, and performing enzymatic reactions over select cells or over a portion of a cell. This method offers a way to simultaneously control the characteristics of the surface to which cells are attached, the type of cells that are in their vicinity, and the kind of media that cells or part of a cell are exposed to. The method is experimentally simple, highly adaptable, and requires no special equipment except for an elastomeric relief that can be readily prepared by rapid prototyping.

The second-order nonlinear optical characteristics of multichromophoric molecules ranging from dipolar symmetry to three-dimensional octupolar symmetry were investigated experimentally and theoretically. The four possible conformers of tetranitrotetrapropoxycalix(4)arene were examined by nanosecond hyper-Raleigh scattering and a newly developed time-resolved femtosecond hyper-Rayleigh scattering procedure. The depolarization ratios indicate the partial octupolar symmetry and the 1,2-alt and 1,3-alt conformers.