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Microbial infections due to biofilms on medical implants can be prevented by antimicrobial coatings on biomaterial surfaces. Mesoporous silica nanoparticles (MSNPs) were synthesized via base-catalyzed sol-gel process at room temperature, functionalized with phenazine-1-carboxamide (PCN) and characterized by UV-visible, FT-IR, DLS, XRD spectroscopic techniques, SEM, TEM, TGA and BET analysis. Native MSNPs, PCN and PCN-MSNPs were evaluated for anti- Candida minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC), Candida albicans ( C . albicans ) biofilms and C . albicans-Staphylococcus aureus ( S . aureus ) polymicrobial biofilm inhibition. PCN-MSNPs were four-fold effective (MIC 3.9 µg mL −1 ; 17.47 µM) and MFC (7.8 µg mL −1 ; 34.94 µM) as compared to pure PCN (MIC 15.6 µg mL −1 ; 69.88 µM) and MFC (31.2 µg mL −1 ; 139.76 µM). PCN-MSNPs inhibited in vitro C . albicans MTCC 227 -S . aureus MTCC 96 biofilms at very low concentration (10 µg mL −1 ; 44.79 µM) as compared to pure PCN (40 µg mL −1 ; 179.18 µM). Mechanistic studies revealed that PCN induced intracellular ROS accumulation in C . albicans MTCC 227, S . aureus MTCC 96 and S . aureus MLS-16 MTCC 2940, reduction in total ergosterol content, membrane permeability, disruption of ionic homeostasis followed by Na + , K + and Ca 2+ leakage leading to cell death in C . albicans MTCC 227 as confirmed by confocal laser scanning micrographs. The silicone urethral catheters coated with PCN-MSNPs (500 µg mL −1 ; 2.23 mM) exhibited no formation of C . albicans MTCC 227 - S . aureus MTCC 96 and C . albicans MTCC 227 - S . aureus MLS -16 MTCC 2940 biofilms. This is the first report on PCN-MSNPs for use as antimicrobial coatings against microbial adhesion and biofilm formation on silicone urethral catheters.

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Multicomponent reaction protocol has been developed for the synthesis of novel pyrimidine fused pyrazolo [3,4-b]pyridine derivatives (7 a-g) and hexahydroquinazoline fused pyrazolo [3,4-b] pyridine derivatives (8 a-i) starting from 3-amino-5carbethoxy-6-trifluoromethyl pyrazolo[3,4-b] pyridine 5. All the synthesized compounds were evaluated for antibacterial as well as antifungal activities and compounds 7 f, 8 a, 8 c and 8 d exhibited promising antibacterial activity. In particular, compound 2,4,6-trifluoro substituted pyrimidine fused pyrazolo [3,4-b]pyridine (7 f) showed very good antibacterial activity against the panel of both Gram-positive and -negative bacterial strains. Hexahydroquinazoline fused pyrazolo [3,4-b]pyridine derivatives (8 f-i) also showed promising antifungal activity and broadspectrum anti-biofilm activity against both Gram-positive and negative bacterial strains. The crystal structure of compound 8 b was solved based on single crystal X-ray diffraction study. Docking studies were performed to identify the interactions of the compounds 7 f with crtM enzyme of Staphylococcus aureus.

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Literature reports suggest that pyrazoles and hydrazides are potential antimicrobial pharmocophores. Considering this fact, a series of nineteen conjugates containing hybrids of bis‐pyrazole scaffolds joined through a hydrazide linker were synthesized and further evaluated for their antimicrobial activity against a panel of Gram‐positive and Gram‐negative bacteria along with Candida albicansMTCC 3017 strain. Although the derivatives exhibited good antibacterial activity, some of the derivatives (13d, 13j, 13l, 13p, and 13r) showed excellent anti‐Candida activity with MICs values of 3.9 μg/ml, which was equipotent to that of the standard Miconazole (3.9 μg/ml), which has inspired us to further explore their anti‐Candida activity. The same compounds were also tested for anti‐biofilm studies against various Candida strains and among them, compounds 13l and 13r efficiently inhibited the formation of fungal biofilms. Field emission scanning electron micrographs revealed that one of the promising compound 13r showed cell damage and in turn cell death of the Candida strain. These potential conjugates (13l and 13r) also demonstrated promising ergosterol biosynthesis inhibition against some of the strains C. albicans, which were further validated through molecular docking studies. In silico computational studies were carried out to predict the binding modes and pharmacokinetic parameters of these conjugates.

A series of novel amide functionalized 1H‐benzo[d]imidazole‐2‐thiol derivatives 4 a‐o were prepared from substituted benzimidazole‐2‐thiol 1 a‐c. All the final compounds were screened for antimicrobial, minimum bactericidal concentration (MBC) and anti‐biofilm activities against Gram‐positive and Gram‐negative bacterial strains. Amongst all the synthesized derivatives, compounds 4 c, 4 e, 4 f, 4 g, 4 k and 4 o exhibiting promising antibacterial activity against various bacterial strains were identified. Moreover, the compound 4 c showed highly significant antimicrobial activity (MIC value of 1.9 μg/mL) and broad‐spectrum anti‐biofilm activity which was identified as a potential lead molecule.