Thin films, rich in primary amines (CNH2), were deposited from nitrogen (N2) or ammonia (NH3) and ethylene (C2H4) with different gas mixture ratios, R, using three different methods: atmospheric‐pressure‐ or low‐pressure plasma polymerisation (PP), and vacuum‐ultraviolet photo‐polymerisation. They are designated H‐plasma‐polymerised ethylene (PPE):N, L‐PPE:N and ultraviolet‐polyethylene (UV‐PE):N, respectively. Of interest in cell‐culture and tissue engineering, all three coating‐types were examined with regard to stability in air and solubility in water, compared with other deposits in the literature that were obtained from single precursors such as allylamine (AA) or n‐heptylamine (HA), PP‐AA and PP‐HA, respectively. The three types of deposits, prepared using comparable R values, were characterised by X‐ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy and atomic force microscopy and found to vary significantly among themselves in regard to their [N]‐ and [NH2] concentrations, and their chemical stabilities during long‐term exposures to air or aqueous solvents. UV‐PE:N and L‐PPE:N films were found to compare very favourably with their best PP‐AA and PP‐HA counterparts; we conclude that the additional important fabrication parameter (the gas mixture ratio, R) is a major asset for preparing stable NH2‐rich organic coatings with optimal properties.

Human U‐937 monocytes are notoriously reluctant to adhere to normally cell‐adhering surfaces, for example tissue‐culture poly(styrene). In earlier work, these laboratories observed that organic thin films prepared by plasma‐ or ultraviolet‐assisted polymerisation, so‐called PVP:N, did facilitate the adhesion and proliferation of U‐937 under the condition that the concentration of primary amines exceed a critical value, [NH2]crit ≥ 4.2 at.%. That criterion being satisfied by pristine Parylene diX AM, we have compared its performance with those of particular types of PVP:N, L‐PPE:N and UV‐PE:N. Here, we report a study of aging of these coating types in atmospheric air, then of time‐dependent adhesion of U‐937 cells. Although there are similarities, the coatings also manifest interesting differences that so far elude detailed understanding.

We present a microfluidic platform for automatic multi-size spheroid formation within constant volume hanging droplets (HDs) from a single inlet loading of a constant cell concentration. The platform introduces three technological improvements over the existing spheroid formation platforms: 1) cell seeding control is achieved by enrichment of a cell solution rather than dilution; 2) cell seeding in each HD is fully independent and pre-programmable at the design stage; 3) the fabricated chip operates well using a hydrophobic PDMS surface, ensuring long-term storage possibility for device usage. Pre-programmed cell seeding densities at each HD are achieved using a "microfluidic funnel" layer, which has an array of cone-shaped wells with increasing apex angles acting as a metering unit. The integrated platform is designed to form, treat, stain, and image multi-size spheroids on-chip. Spheroids can be analyzed on-chip or easily transferred to conventional well plates for further processing. Empirically, enrichment factors up to 37× have been demonstrated, resulting in viable spheroids of diameters ranging from 230-420 μm and 280-530 μm for OV90 and TOV112D cell lines, respectively. We envision that microfluidic funnels and single inlet multi-size spheroid (SIMSS) chips will find broad application in 3D biological assays where size-dependent responses are expected, including chemoresponse assays, photodynamic therapy assays, and other assays involving drug transport characterization in drug discovery.

. Significance: The primary method of COVID-19 detection is reverse transcription polymerase chain reaction (RT-PCR) testing. PCR test sensitivity may decrease as more variants of concern arise and reagents may become less specific to the virus. Aim: We aimed to develop a reagent-free way to detect COVID-19 in a real-world setting with minimal constraints on sample acquisition. The machine learning (ML) models involved could be frequently updated to include spectral information about variants without needing to develop new reagents. Approach: We present a workflow for collecting, preparing, and imaging dried saliva supernatant droplets using a non-invasive, label-free technique—Raman spectroscopy—to detect changes in the molecular profile of saliva associated with COVID-19 infection. Results: We used an innovative multiple instance learning-based ML approach and droplet segmentation to analyze droplets. Amongst all confounding factors, we discriminated between COVID-positive and COVID-negative individuals yielding receiver operating coefficient curves with an area under curve (AUC) of 0.8 in both males (79% sensitivity and 75% specificity) and females (84% sensitivity and 64% specificity). Taking the sex of the saliva donor into account increased the AUC by 5%. Conclusion: These findings may pave the way for new rapid Raman spectroscopic screening tools for COVID-19 and other infectious diseases.

Predicting patient responses to anticancer drugs is a major challenge both at the drug development stage and during cancer treatment. Tumor explant culture platforms (TECPs) preserve the native tissue architecture and are well-suited for drug response assays. However, tissue longevity in these models is relatively low. Several methodologies have been developed to address this issue, although no study has compared their efficacy in a controlled fashion. We investigated the effect of two variables in TECPs, specifically, the tissue size and culture vessel on tissue survival using micro-dissected tumor tissue (MDT) and tissue slices which were cultured in microfluidic chips and plastic well plates. Tumor models were produced from ovarian and prostate cancer cell line xenografts and were matched in terms of the specimen, total volume of tissue, and respective volume of medium in each culture system. We examined morphology, viability, and hypoxia in the various tumor models. Our observations suggest that the viability and proliferative capacity of MDTs were not affected during the time course of the experiments. In contrast, tissue slices had reduced proliferation and showed increased cell death and hypoxia under both culture conditions. Tissue slices cultured in microfluidic devices had a lower degree of hypoxia compared to those in 96-well plates. Globally, our results show that tissue slices have lower survival rates compared to MDTs due to inherent diffusion limitations, and that microfluidic devices may decrease hypoxia in tumor models.