Disposable electrochemical biosensors for the detection of bacteria in the light of antimicrobial resistance.

Persistent and inappropriate use of antibiotics is causing rife antimicrobial resistance (AMR) worldwide. Common bacterial infections are thus becoming increasingly difficult to treat without the use of last resort antibiotics. This has necessitated a situation where it is imperative to confirm the infection to be bacterial, before treating it with antimicrobial speculatively. Conventional methods of bacteria detection are either culture based which take anywhere between 24 and 96 hor require sophisticated molecular analysis equipment with libraries and trained operators. These are difficult propositions for resource limited community healthcare setups of developing or less developed countries. Customized, inexpensive, point-of-care (PoC) biosensors are thus being researched and developed for rapid detection of bacterial pathogens. The development and optimization of disposable sensor substrates is the first and crucial step in development of such PoC systems. The substrates should facilitate easy charge transfer, a high surface to volume ratio, be tailorable by the various bio-conjugation chemistries, preserve the integrity of the biorecognition element, yet be inexpensive. Such sensor substrates thus need to be thoroughly investigated. Further, if such systems were made disposable, they would attain immunity to biofouling. This article discusses a few potential disposable electrochemical sensor substrates deployed for detection of bacteria for environmental and healthcare applications. The technologies have significant potential in helping reduce bacterial infections and checking AMR. This could help save lives of people succumbing to bacterial infections, as well as improve the overall quality of lives of people in low- and middle-income countries.

Synthesis, spectral characterization, crystal structure, cytotoxicity and apoptosis-Inducing activity of two derivatives of 2-hydroxy-1,4-naphthaquinone.

A phenaxazone compound [5H-Benzo[a]phenoxazin-5-one (BP)] along with an aminoquinone[2-[(o-hydroxyphenyl)amino]-1,4-naphthaquinone (HAN)] derivatives were synthesized from lawsone using ultrasound irradiation technique. The structure of the compounds were characterized by elemental analysis and various spectral studies. Optoelectronic properties were studied using Schrodinger material science suit (2015). The compounds exhibit fluorescence emission in longer wave length it may find applications in photodynamic therapy. Single crystal X-ray diffraction studies reveals that the compound BP crystallizes in monoclinic space group. The antioxidant activity of HAN and BP were determined using DPPH radical scavenging assay and the results indicate that both the compounds have good antioxidant capacity, HAN having more scavenging activity than BP. Lead molecules were identified using in silico molecular docking studies as a green chemistry approach. iGEMDOCK, GOLD and Schrödinger softwares were used for these studies. The docking studies reveal that the structural modification of the parent compound gave more active compounds making them promising lead molecules. The lead molecules were subjected to in vitro studies. The cytotoxicity of BP and HAN was studied using human breast cancer (SKBR3) cell lines. The IC50 value of HAN was found to be 19.8µM while BP was found to have cell viability, less than 10% even at 25µM concentration. The chemotherapeutic agents kill the cancer cells mainly through apoptosis. HAN and BP were subjected to apoptosis studies. BP was found to more active than HAN. Thus it can be suggested that the mechanism of cell death may be through apoptosis.