Nasker, S. S. | Search bioRxiv

bioRxiv2025

Enhancing the biocorrosion resistance and biocompatibility of Aluminium substrates using Graphene Oxide-PEDOT:PSS Hybrid Coating

Biofilm-associated infections on medical devices remain a major clinical challenge due to antimicrobial resistance, biofouling, and biocorrosion, compromising implant longevity and biocompatibility. Conventional biomedical devices utilizing stainless steel and titanium exhibit limited resistance to biofilm-prone physiological environments, necessitating development of next-generation implant materials. While alumina (Al2O3) is favored for its bio-inertness, it raises concerns like leaching and systemic toxicity. Aluminum alloy 1050 (AA1050) offers intrinsic corrosion resistance via a passive oxide layer under dry conditions but remains prone to microbiologically influenced corrosion (MIC) under humid conditions. In the recent years, graphene family of materials have emerged as promising surface coating for metals and alloys due to their strong barrier properties and antimicrobial efficacy. Most graphene derivatives like GO require relatively higher concentrations to achieve antimicrobial activity, however compromising biocompatibility, limiting in vivo human uses. This study addresses these caveats by exploring GO activity at lower concentrations (50-500 {micro}g/ml) on AA1050 to achieve a balance between antimicrobial efficiency and cytocompatibility. Additionally, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS, 1 {micro}g/ml) was integrated with GO to form a hybrid coating on Al (Al_GO/P), to improve GO adhesion, and corrosion resistance. Biological evaluations against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Candida albicans (C. albicans) demonstrated superior antifouling and antimicrobial efficacy of Al_GO/P substrates compared to GO-coated Al (Al_GO) and bare Al surfaces. Corrosion rate, FESEM, ICP-MS, and cytotoxicity analyses further confirmed reduced biocorrosion, minimal ion leaching, along with enhanced biocompatibility of the hybrid coated surfaces. Al_GO/P containing GO at 100 and 250 {micro}g/ml concentration achieved the optimal balance between antimicrobial activity and biocompatibility and can be used as in vivo implant materials. Hence, this technology can be implemented towards surface modification of biomedical devices to mitigate periprosthetic infections as well as support ex vivo applications requiring durable antimicrobial performance.

microbiology↗

bioRxiv2025

Enhanced Formulation of Precision Probiotics through Active Machine Learning

The human gut microbiome is crucial to health, with dysbiosis increasingly linked to disease. Precision probiotics offer a promising approach to restoring microbial balance, but ensuring probiotic viability through gastrointestinal transit remains a challenge. This study applies an advanced active machine learning (ML) approach to predict how excipients affect the growth of Lactobacillus plantarum, a commonly used probiotic. State-of-the-art experiments were carried out to complement the ML study. Starting with five known excipient- probiotic interactions, we apply active ML over three rounds to predict the effects of 116 excipients, iteratively refining model certainty and accuracy. Five ML models--Neural Networks, Gradient Boosting, Logistic Regression, Random Forest, and Support Vector Machines--were trained and evaluated, with the final model achieving certainty levels close to 90%. Unlike previous methods, which retrained new models per iteration, our approach continuously optimized a single model, enhancing prediction stability and reducing error. These results highlight the potential of active ML to support accurate excipient selection in probiotic formulations.

bioinformatics↗