Biosensors for Klebsiella pneumoniae with Molecularly Imprinted Polymer (MIP) Technique.

Nosocomial infection is one of the most important problems that occurs in hospitals, as it directly affects susceptible patients or patients with immune deficiency. Klebsiella pneumoniae (K. pneumoniae) is the most common cause of nosocomial infections in hospitals. K. pneumoniae can cause various diseases such as pneumonia, urinary tract infections, septicemias, and soft tissue infections, and it has also become highly resistant to antibiotics. The principal routes for the transmission of K. pneumoniae are via the gastrointestinal tract and the hands of hospital personnel via healthcare workers, patients, hospital equipment, and interventional procedures. These bacteria can spread rapidly in the hospital environment and tend to cause nosocomial outbreaks. In this research, we developed a MIP-based electrochemical biosensor to detect K. pneumoniae. Quantitative detection was performed using an electrochemical technique to measure the changes in electrical signals in different concentrations of K. pneumoniae ranging from 10 to 105 CFU/mL. Our MIP-based K. pneumoniae sensor was found to achieve a high linear response, with an R2 value of 0.9919. A sensitivity test was also performed on bacteria with a similar structure to that of K. pneumoniae. The sensitivity results show that the MIP-based K. pneumoniae biosensor with a gold electrode was the most sensitive, with a 7.51 (% relative current/log concentration) when compared with the MIP sensor applied with Pseudomonas aeruginosa and Enterococcus faecalis, where the sensitivity was 2.634 and 2.226, respectively. Our sensor was also able to achieve a limit of detection (LOD) of 0.012 CFU/mL and limit of quantitation (LOQ) of 1.61 CFU/mL.

Virus MIP-composites for SARS-CoV-2 detection in the aquatic environment.

SARS-CoV-2 is the virus responsible for causing the global COVID-19 pandemic. Identifying the presence of this virus in the environment could potentially improve the effectiveness of disease control measures. Environmental SARS-CoV-2 monitoring may become increasingly demanded in areas where the available testing methods are ineffective. In this study, we present an electrochemical polymer composites biosensor for measuring SARS-CoV-2 whole-virus particles in the environment. The sensitized layer was prepared from molecularly imprinted polymer (MIP) composites of inactivated SARS-CoV-2. Testing demonstrated increased sensor signaling with SARS-CoV-2 specifically, while lower responses were observed to the negative controls, H5N1 influenza A virus and non-imprinted polymers (NIPs). This sensor detected SARS-CoV-2 at concentrations as low as 0.1 fM in buffer and samples prepared from reservoir water with a 3 log-scale linearity.

Electrochemical Biosensor Based on Surface Imprinting for Zika Virus Detection in Serum.

Zika virus (ZIKV) is a flavivirus that was first identified in 1947. Initially, the virus was of little concern for health authorities given there were very few casualties among those suffering an infection. As such, only limited studies were performed on ZIKV. Recently, the viral infection has been linked to microcephaly in infants, which has prompted a dramatic increase in scientific interest in ZIKV research, including methods to allow for rapid virus identification. In this work we report the development of a new type of ZIKV electrochemical biosensor based on surface imprinted polymers and graphene oxide composites. The biosensor was used to detect ZIKV by measuring changes in the electrical signal with changing virus concentrations in buffer and serum using standard electrochemical techniques. The detection limit of our method is similar to the detection limit of the real-time quantitative reverse transcription PCR method.

Small-Molecule Dengue Virus Co-imprinting and Its Application as an Electrochemical Sensor.

Polymers can be synthesized to recognize small molecules. This is achieved by introducing the target molecule during monomer self-assembly, where they can be incorporated during cross-linking polymerization. Following additional pre-processing, the material obtained can then be applied as a sensing layer for these molecules in many applications. The sensitivity of the polymers depends on the "active sites" imprinted on the surface. Increasing the number of active sites on the polymers surface can be achieved by using nanoparticles as a platform to support and concentrate the molecules for imprinting. In this work, we report the first use of dengue virus as a supporting nanoparticle to make for a more effective polymer composite sensor for the detection of bisphenol A (BPA), which is an environmental contaminant. The dengue virus has a nanoparticle size of around 100 nm and its surface provides regions where lipids and hydrophobic compounds can bind, making it an ideal support. The mixing of BPA with dengue prior to monomer self-assembly led to imprinted polymer surfaces with much higher density BPA binding sites and a limit of detection of 0.1 pm. We demonstrate that a BPA-dengue co-imprinting polymer composite sensor shows a very high sensitivity for BPA, but with lower production costs and technical requirements than other comparable methods.

An influenza A virus agglutination test using antibody-like polymers.

Antibodies are commonly used in diagnostic routines to identify pathogens. The testing protocols are relatively simple, requiring a certain amount of a specific antibody to detect its corresponding pathogen. Antibody functionality can be mimicked by synthesizing molecularly imprinted polymers (MIPs), i.e. polymers that can selectively recognize a given template structure. Thus, MIPs are sometimes termed 'plastic antibody (PA)'. In this study, we have synthesized new granular MIPs using influenza A virus templates by precipitation polymerization. The selective binding of influenza A to the MIP particles was assessed and subsequently contrasted with other viruses. The affinities of influenza A virus towards the MIP was estimated based on an agglutination test by measuring the amount of influenza subtypes absorbed onto the MIPs. The MIPs produced using the H1N1 template showed specific reactivity to H1N1 while those produced using H5N1 and H3N2 templates showed cross-reactivity.

H5N1 Virus Plastic Antibody Based on Molecularly Imprinted Polymers.

Normally, antibodies against influenza A have been prepared from viable virus or an engineered strain in certain hosts or cultured media. Two factors concerning antibody production are obvious. The obtaining antibody that is a kind of biomolecule has to be handled carefully, e.g., to be kept in a refrigerator. Furthermore, when the virus strain is highly pathogenic, such as H5N1, antibody production has to be done carefully in a high-level biosafety lab. Here, we show how to produce an antibody against H5N1 from a polymeric material using inactivated virus which can be conducted in a low-level biosafety lab. The process is based on imprinting the whole virus on a polymer surface to form molecularly imprinted polymers (MIPs). The MIPs show some properties of H5N1 antibody as they recognize H5N1 and have some important antibody activity. The H5N1 MIPs are not to be considered biomaterial, so they can be stored at room temperature and thus do not need any special care.