Selected landscape phage probe as selective recognition interface for sensitive total prostate-specific antigen immunosensor

Advancements in ovarian cancer immunodiagnostics and therapeutics via phage display technology

Ovarian cancer, ranking as the seventh most prevalent malignancy among women globally, faces significant challenges in diagnosis and therapeutic intervention. The difficulties in early detection are amplified by the limitations and inefficacies inherent in current screening methodologies, highlighting a pressing need for more efficacious diagnostic and treatment strategies. Phage display technology emerges as a pivotal innovation in this context, utilizing extensive phage-peptide libraries to identify ligands with specificity for cancer cell markers, thus enabling precision-targeted therapeutic strategies. This technology promises a paradigm shift in ovarian cancer management, concentrating on targeted drug delivery systems to improve treatment accuracy and efficacy while minimizing adverse effects. Through a meticulous review, this paper evaluates the revolutionary potential of phage display in enhancing ovarian cancer therapy, representing a significant advancement in combating this challenging disease. Phage display technology is heralded as an essential instrument for developing effective immunodiagnostic and therapeutic approaches in ovarian cancer, facilitating early detection, precision-targeted medication, and the implementation of customized treatment plans.

Phage Display's Prospects for Early Diagnosis of Prostate Cancer

Prostate cancer (PC) is the second most diagnosed cancer among men. It was observed that early diagnosis of disease is highly beneficial for the survival of cancer patients. Therefore, the extension and increasing quality of life of PC patients can be achieved by broadening the cancer screening programs that are aimed at the identification of cancer manifestation in patients at earlier stages, before they demonstrate well-understood signs of the disease. Therefore, there is an urgent need for standard, sensitive, robust, and commonly available screening and diagnosis tools for the identification of early signs of cancer pathologies. In this respect, the "Holy Grail" of cancer researchers and bioengineers for decades has been molecular sensing probes that would allow for the diagnosis, prognosis, and monitoring of cancer diseases via their interaction with cell-secreted and cell-associated PC biomarkers, e.g., PSA and PSMA, respectively. At present, most PSA tests are performed at centralized laboratories using high-throughput total PSA immune analyzers, which are suitable for dedicated laboratories and are not readily available for broad health screenings. Therefore, the current trend in the detection of PC is the development of portable biosensors for mobile laboratories and individual use. Phage display, since its conception by George Smith in 1985, has emerged as a premier tool in molecular biology with widespread application. This review describes the role of the molecular evolution and phage display paradigm in revolutionizing the methods for the early diagnosis and monitoring of PC.

Bioscreening specific peptide-expressing phage and its application in sensitive dual-mode immunoassay of SARS-CoV-2 spike antigen

Biorecognition components with high affinity and selectivity are vital in bioassay to diagnose and treat epidemic disease. Herein a phage display strategy of combining single-amplification-panning with non-amplification-panning was developed, by which a phage displaying cyclic heptapeptide ACLDWLFNSC (peptide J4) with good affinity and specificity to SARS-CoV-2 spike protein (SP) was identified. Molecular docking suggests that peptide J4 binds to S2 subunit by hydrogen bonding and hydrophobic interaction. Then the J4-phage was used as the capture antibody to establish phage-based chemiluminescence immunoassay (CLIA) and electrochemical impedance spectroscopy (EIS) analytical systems. The as-proposed dual-modal immunoassay platform exhibited good sensitivity and reliability in SARS-CoV-2 SP and pseudovirus assay. The limit of detection for SARS-CoV-2 SP by EIS immunoassay is 0.152 pg/mL, which is dramatically lower than that of 42 pg/mL for J4-phage based CLIA. Further, low to 40 transducing units (TU)/mL, 10 TU/mL SARS-CoV-2 pseudoviruses can be detected by the proposed J4-phage based CLIA and electrochemical immunosensor, respectively. Therefore, the as-developed dual mode immunoassays are potential methods to detect SARS-CoV-2. It is also expected to explore various phages with specific peptides to different targets for bioanalysis.

Rapid and reliable ultrasensitive detection of pathogenic H9N2 viruses through virus-binding phage nanofibers decorated with gold nanoparticles

The rapid and sensitive detection of pathogenic viruses is important for controlling pandemics. Herein, a rapid, ultrasensitive, optical biosensing scheme was developed to detect avian influenza virus H9N2 using a genetically engineered filamentous M13 phage probe. The M13 phage was genetically engineered to bear an H9N2-binding peptide (H9N2BP) at the tip and a gold nanoparticle (AuNP)-binding peptide (AuBP) on the sidewall to form an engineered phage nanofiber, M13@H9N2BP@AuBP. Simulated modelling showed that M13@H9N2BP@AuBP enabled a 40-fold enhancement of the electric field enhancement in surface plasmon resonance (SPR) compared to conventional AuNPs. Experimentally, this signal enhancement scheme was employed for detecting H9N2 particles with a sensitivity down to 6.3 copies/mL (1.04 × 10-5 fM). The phage-based SPR scheme can detect H9N2 viruses in real allantoic samples within 10 min, even at very low concentrations beyond the detection limit of quantitative polymerase chain reaction (qPCR). Moreover, after capturing the H9N2 viruses on the sensor chip, the H9N2-binding phage nanofibers can be quantitatively converted into plaques that are visible to the naked eye for further quantification, thereby allowing us to enumerate the H9N2 virus particles through a second mode to cross-validate the SPR results. This novel phage-based biosensing strategy can be employed to detect other pathogens because the H9N2-binding peptides can be easily switched with other pathogen-binding peptides using phage display technology.

Sensitive Lateral Flow Immunoassay Based on Specific Peptide and Superior Oxidase Mimics with a Universal Dual-Mode Significant Signal Amplification

Rapid and sensitive antigen detection using a lateral flow immunoassay (LFIA) is crucial for diagnosing infectious diseases due to its simplicity, speed, and user-friendly features. However, it remains a critical issue to explore specific biorecognition elements and powerful signal amplification. In this study, taking SARS-CoV-2 as a proof of concept, a specific peptide, WFLNDSELIML, binding to the SARS-CoV-2 spike (S) antigen was identified by a nonamplified biopanning method, which exhibited high affinity to the target, with a dissociation constant of 9.29 ± 1.55 nM. Molecular docking analysis reveals that this peptide binds to the N-terminal domain of the SARS-CoV-2 S antigen. Then, using this peptide as a capture probe and angiotensin-converting enzyme 2 as a detection probe, a peptide-based lateral flow immunoassay (pLFIA) for the sensitive detection of the SARS-CoV-2 S antigen without any antibody was developed, for which a polydopamine nanosphere (PDA)@MnO2 nanocomposite with excellent oxidase-like activity was used as a colorimetric label, exhibiting dual-mode remarkable signal amplification of natural melanin and on-demand nanozyme catalytic enhancement. The PDA@MnO2-based pLFIA is capable of detecting the SARS-CoV-2 S antigen with a limit of detection of 8.01 pg/mL, which is 18.7 times lower than that of a conventional pLFIA tagged with gold nanoparticles. Additionally, the as-proposed PDA@MnO2-based pLFIA can detect up to 150 transduction units/mL SARS-CoV-2 pseudoviruses spiked in saliva samples. Given the outstanding analytical performance, the proposed PDA@MnO2-based pLFIA may offer a reliable option for the rapid diagnosis of SARS-CoV-2.

Biopanning of specific peptide for SARS-CoV-2 nucleocapsid protein and enzyme-linked immunosorbent assay-based antigen assay

The ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly spread worldwide which triggered serious public health issues. The search for rapid and accurate diagnosis, effective prevention, and treatment is urgent. The nucleocapsid protein (NP) of SARS-CoV-2 is one of the main structural proteins expressed and most abundant in the virus, and is considered a diagnostic marker for the accurate and sensitive detection of SARS-CoV-2. Herein, we report the screening of specific peptides from the pIII phage library that bind to SARS-CoV-2 NP. The phage monoclone expressing cyclic peptide N1 (peptide sequence, ACGTKPTKFC, with C&C bridged by disulfide bonding) specifically recognizes SARS-CoV-2 NP. Molecular docking studies reveal that the identified peptide is bound to the "pocket" region on the SARS-CoV-2 NP N-terminal domain mainly by forming a hydrogen bonding network and through hydrophobic interaction. Peptide N1 with the C-terminal linker was synthesized as the capture probe for SARS-CoV-2 NP in ELISA. The peptide-based ELISA was capable of assaying SARS-CoV-2 NP at concentrations as low as 61 pg/mL (∼1.2 pM). Furthermore, the as-proposed method could detect the SARS-CoV-2 virus at limits as low as 50 TCID₅₀ (median tissue culture infective dose)/mL. This study demonstrates that selected peptides are powerful biomolecular tools for SARS-CoV-2 detection, providing a new and inexpensive method of rapidly screening infections as well as rapidly diagnosing coronavirus disease 2019 patients.

Recombinant antibodies by phage display for bioanalytical applications

Antibody phage display, aimed at preparing antibodies to defined antigens, is a useful replacement for hybridoma technology. The phage system replaces all work stages that follow animal immunization with simple procedures for manipulating DNA and bacteria. It enables the time needed to generate stable antibody-producing clones to be shortened considerably, making the process noticeably cheaper. Antibodies prepared by phage display undergo several affinity selection steps and can be used as selective receptors in biosensors. This article briefly describes the techniques used in the making of phage antibodies to various antigens. The possibilities and prospects are discussed of using phage antibodies as selective agents in analytical systems, including biosensors.

Modified Bacteriophage for Tumor Detection and Targeted Therapy

Malignant tumor is one of the leading causes of death in human beings. In recent years, bacteriophages (phages), a natural bacterial virus, have been genetically engineered for use as a probe for the detection of antigens that are highly expressed in tumor cells and as an anti-tumor reagent. Furthermore, phages can also be chemically modified and assembled with a variety of nanoparticles to form a new organic/inorganic composite, thus extending the application of phages in biological detection and tumor therapeutic. This review summarizes the studies on genetically engineered and chemically modified phages in the diagnosis and targeting therapy of tumors in recent years. We discuss the advantages and limitations of modified phages in practical applications and propose suitable application scenarios based on these modified phages.

Discovery of a Phage Peptide Specifically Binding to the SARS-CoV-2 Spike S1 Protein for the Sensitive Phage-Based Enzyme-Linked Chemiluminescence Immunoassay of the SARS-CoV-2 Antigen

The COVID-19 pandemic has led to a global crisis with devastating effects on public healthcare and the economy. Sensitive detection of SARS-CoV-2 is the key to diagnose and control its spread. The spike (S) protein is an abundant viral transmembrane protein and a suitable target protein for the selective recognition of SARS-CoV-2. Here, we report that with bovine serum albumin prescreening, a specific phage peptide targeting SARS-CoV-2 S1 protein was biopanned with the pIII phage display library. The identified phage #2 expressing the peptide (amino acid sequence: NFWISPKLAFAL) shows high affinity to the target with a dissociation constant of 3.45 ± 0.58 nM. Furthermore, the identified peptide shows good specificity with a binding site at the N-terminal domain of the S1 subunit through a hydrogen bond network and hydrophobic interaction, supported by molecular docking. Then, a sandwiched phage-based enzyme-linked chemiluminescence immunoassay (ELCLIA) was established by using phage #2 as a bifunctional probe capable of SARS-CoV-2 S1 antigen recognition and signal amplification. After optimizing the conditions, the proposed phage ELCLIA exhibited good sensitivity, and as low as 78 pg/mL SARS-CoV-2 S1 could be detected. This method can be applied to detect as low as 60 transducing units (TU)/mL SARS-CoV-2 pseudovirus in 50% saliva. Therefore, specific phage peptides have good prospects as powerful biological recognition probes for immunoassay detection and biomedical applications.

Phage-Displayed Mimotopes of SARS-CoV-2 Spike Protein Targeted to Authentic and Alternative Cellular Receptors

The evolution of the SARS-CoV-2 virus during the COVID-19 pandemic was accompanied by the emergence of new heavily mutated viral variants with increased infectivity and/or resistance to detection by the human immune system. To respond to the urgent need for advanced methods and materials to empower a better understanding of the mechanisms of virus’s adaptation to human host cells and to the immuno-resistant human population, we suggested using recombinant filamentous bacteriophages, displaying on their surface foreign peptides termed “mimotopes”, which mimic the structure of viral receptor-binding sites on the viral spike protein and can serve as molecular probes in the evaluation of molecular mechanisms of virus infectivity. In opposition to spike-binding antibodies that are commonly used in studying the interaction of the ACE2 receptor with SARS-CoV-2 variants in vitro, phage spike mimotopes targeted to other cellular receptors would allow discovery of their role in viral infection in vivo using cell culture, tissue, organs, or the whole organism. Phage mimotopes of the SARS-CoV-2 Spike S1 protein have been developed using a combination of phage display and molecular mimicry concepts, termed here “phage mimicry”, supported by bioinformatics methods. The key elements of the phage mimicry concept include: (1) preparation of a collection of p8-type (landscape) phages, which interact with authentic active receptors of live human cells, presumably mimicking the binding interactions of human coronaviruses such as SARS-CoV-2 and its variants; (2) discovery of closely related amino acid clusters with similar 3D structural motifs on the surface of natural ligands (FGF1 and NRP1), of the model receptor of interest FGFR and the S1 spike protein; and (3) an ELISA analysis of the interaction between candidate phage mimotopes with FGFR3 (a potential alternative receptor) in comparison with ACE2 (the authentic receptor).

Recognition elements based on the molecular biological techniques for detecting pesticides in food: A review

Excessive use of pesticides can cause contamination of the environment and agricultural products that are directly threatening human life and health. Therefore, in the process of food safety supervision, it is crucial to conduct sensitive and rapid detection of pesticide residues. The recognition element is the vital component of sensors and methods for fast testing pesticide residues in food. Improper recognition elements may lead to defects of testing methods, such as poor stability, low sensitivity, high economic costs, and waste of time. We can use the molecular biological technique to address these challenges as a good strategy for recognition element production and modification. Herein, we review the molecular biological methods of five specific recognition elements, including aptamers, genetic engineering antibodies, DNAzymes, genetically engineered enzymes, and whole-cell-based biosensors. In addition, the application of these identification elements combined with biosensor and immunoassay methods in actual detection was also discussed. The purpose of this review was to provide a valuable reference for further development of rapid detection methods for pesticide residues.

Strategies for Surface Immobilization of Whole Bacteriophages: A Review

Bacteriophage immobilization is a key unit operation in emerging biotechnologies, enabling new possibilities for biodetection of pathogenic microbes at low concentration, production of materials with novel antimicrobial properties, and fundamental research on bacteriophages themselves. Wild type bacteriophages exhibit extreme binding specificity for a single species, and often for a particular subspecies, of bacteria. Since their specificity originates in epitope recognition by capsid proteins, which can be altered by chemical or genetic modification, their binding specificity may also be redirected toward arbitrary substrates and/or a variety of analytes in addition to bacteria. The immobilization of bacteriophages on planar and particulate substrates is thus an area of active and increasing scientific interest. This review assembles the knowledge gained so far in the immobilization of whole phage particles, summarizing the main chemistries, and presenting the current state-of-the-art both for an audience well-versed in bioconjugation methods as well as for those who are new to the field.

Electrochemical prostate-specific antigen biosensors based on electroconductive nanomaterials and polymers

Prostate cancer (PCa), the second most malignant neoplasm in men, is also the fifth leading cause of cancer-related deaths in men globally. Unfortunately, this malignancy remains largely asymptomatic until late-stage emergence when treatment is limited due to the lack of effective metastatic PCa therapeutics. Due to these limitations, early PCa detection through prostate-specific antigen (PSA) screening has become increasingly important, resulting in a more than 50% decrease in mortality. Conventional assays for PSA detection, such as enzyme-linked immunosorbent assay (ELISA), are labor intensive, relatively expensive, operator-dependent and do not provide adequate sensitivity. Electrochemical biosensors overcome these limitations because they are rapid, cost-effective, simple to use and ultrasensitive. This article reviews electrochemical PSA biosensors using electroconductive nanomaterials such as carbon-, metal-, metal oxide- and peptide-based nanostructures, as well as polymers to significantly improve conductivity and enhance sensitivity. Challenges associated with the development of these devices are discussed thus providing additional insight into their analytic strength as well as their potential use in early PCa detection.

Phage-Based Sensors in Medicine: A Review

Bacteriophages are interesting entities on the border of biology and chemistry. In nature, they are bacteria parasites, while, after genetic manipulation, they gain new properties, e.g., selectively binding proteins. Owing to this, they may be applied as recognition elements in biosensors. Combining bacteriophages with different transducers can then result in the development of innovative sensor designs that may revolutionize bioanalytics and improve the quality of medical services. Therefore, here, we review the use of bacteriophages, or peptides from bacteriophages, as new sensing elements for the recognition of biomarkers and the construction of the highly effective diagnostics tools.

Colorimetric Assay of Bacterial Pathogens Based on Co3O4 Magnetic Nanozymes Conjugated with Specific Fusion Phage Proteins and Magnetophoretic Chromatography

It is important to detect pathogens rapidly, sensitively, and selectively for clinical medicine, homeland security, food safety, and environmental control. We report here a specific and sensitive colorimetric assay that incorporated a bovine serum albumin-templated Co₃O₄ magnetic nanozyme (Co₃O₄ MNE) with a novel specific fusion phage protein and magnetophoretic chromatography to detect Staphylococcus aureus. The Co₃O₄ MNE was conjugated to S. aureus-specific fusion-pVIII (Co₃O₄ MNE@fusion-pVIII), screened from the S. aureus-specific phage AQTFLGEQD (the phage monoclone is denoted by the peptide sequence). The as-prepared triple-functional Co₃O₄ MNE@fusion-pVIII particles were capable of capturing S. aureus in sterile milk, which were then isolated from milk magnetically. Assisted by polyethylene glycol, the Co₃O₄ MNE@fusion-pVIII@S. aureus complex was separated from the free Co₃O₄ MNE@fusion-pVIII by magnetophoretic chromatography in an external magnetic field. After transferring the isolated Co₃O₄ MNE@fusion-pVIII@S. aureus complexes into a 96-well plate, diammonium salt of 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) and H₂O₂ were added to develop color because of the peroxidase mimetics activity of the Co₃O₄ MNE. A S. aureus concentration within 10-10,000 cfu/mL in milk can be detected (detection limit: 8 cfu/mL). The as-developed method is simple, cost-efficient, and sensitive, which is useful for rapidly diagnosing pathogenic bacteria and helpful to prevent disease outbreaks induced by pathogens in developing countries.

A signal amplification strategy for prostate specific antigen detection via releasing oxidase-mimics from coordination nanoparticles by alkaline phosphatase

A novel signal amplification method for prostate specific antigen (PSA) is developed by freeing fluorescein with photoinduced oxidase-like activity from coordination nanoparticles (CNPs) in the presence of alkaline phosphatase (ALP). CNPs loaded with fluorescein (F@CNPs) are obtained in aqueous solution by self-assembly using Tb³⁺ as metal ion, guanosine monophosphate (5'-GMP) as ligand, and fluorescein as signal molecule. The F@CNPs display outstanding properties of simple synthesis, low cost, good water solubility, negligible leakage and satisfactory load capacity. Fluorescein is quantitatively encapsulated in CNPs with a binding ratio of 92.72%. Meanwhile, ALP can specifically hydrolyze the phosphate group of 5'-GMP ligand, triggering the destruction of F@CNPs and leakage of fluorescein. Fluorescein, a photoinduced oxidase mimic, can catalyze the oxidation of non-fluorescent Amplex UltraRed (AUR) into fluorescent resorufin under LED lamp. This strategy exhibits good sensitivity for ALP detection. In addition, a new immunoassay for PSA is validated by labelling ALP on PSA antibody. The low detection limit of 0.04 ng mL^-1 in detecting PSA is appropriate for PSA detection in real samples. Therefore, the work not only establishes a new strategy for ALP and PSA determination, but also provides a new conception for putting photoinduced oxidase-like fluorescein in practical application.

Advances in prostate specific antigen biosensors-impact of nanotechnology

Prostate cancer is one of the most dangerous and deadly cancers in elderly men. Early diagnosis using prostate-specific antigen (PSA) facilitates disease detection, management and treatment. Biosensors have recently been used as sensitive, selective, inexpensive and rapid diagnostic tools for PSA detection. In this review, a variety of PSA biosensors such as aptasensors, peptisensors and immunesensors are highlighted. These use aptamers, peptides and antibodies in the biorecognition element, respectively, and can detect PSA with very high sensitivity via electrochemical, electrochemiluminescence, fluorescence and surface-enhanced Raman spectroscopy. To improve the sensitivity of most of these PSA biosensors, different nanostructured materials have played a critical role.

Tailored monoclonal antibody as recognition probe of immunosensor for ultrasensitive detection of silk fibroin and use in the study of archaeological samples

The ultrasensitive detection of fibroin in unearthed silk relics has great significance for investigating the origin and transmission of silk. In this study, an anti-fibroin monoclonal antibody was successfully prepared through animal immunization. Next, a label-free electrochemical immunosensor was fabricated using layer-by-layer self-assembly technology, and an indirect enzyme-linked immunosorbent assay (ELISA) was proposed. The two methods exhibited excellent sensitivity and specificity in the detection of silk fibroin, while the immunosensor showed a wider quantitative detection range (0.1-100 ng mL^-1) and a lower detection limit (0.051 ng mL^-1) than ELISA (10-100 ng mL^-1 and 8.71 ng mL^-1). Furthermore, the performance of the immunosensor was superior in archaeological sample detection. Taking advantage of the well-prepared monoclonal antibody, the two proposed immunological assays demonstrate tremendous potential for the ultrasensitive detection of silk fibroin, which can make great contributions to exploring the origin and transmission routes of ancient silks.

Sensitivity and reproducibility improvements in a human plasma immunoassay with removal of clotting factors

Interferences in human plasma immunoassay are severe challenge that affects the sensitivity and reproducibility of the assay. The clotting factor fibrinogen is a negatively charged protein and is one of the most common sources of interference in immunoassays, and its removal increases the sensitivity and reproducibility. Here, we present a highly sensitive and reproducible method for the detection of prostate specific antigen (PSA) in human plasma immunoassays. Protamine sulfate, a highly positively charged protein, was used to precipitate fibrinogen via ionic interaction to improve the sensitivity and reproducibility of human plasma immunoassay. In a sandwich ELISA for PSA using plasma and protamine-treated plasma samples, the limit of detection was improved from 413 pg/mL in plasma to 235 pg/mL in protamine-treated plasma samples, and the coefficient of variation known as a measure of reproducibility was significantly lowered by protamine treatment. The use of protamine sulfate in human plasma immunoassays for detection of PSA using quartz crystal microbalance (QCM) biosensors resulted in increased sensitivity and reproducibility by about 2-fold and 3-fold, respectively, relative to when not using protamine sulfate. Based on these results, protamine sulfate was the best choice to increase the sensitivity and reproducibility in immunoassays using plasma samples.

Tackling the Challenges of Enzymatic (Bio)Fuel Cells

The ever-increasing demands for clean and sustainable energy sources combined with rapid advances in biointegrated portable or implantable electronic devices have stimulated intensive research activities in enzymatic (bio)fuel cells (EFCs). The use of renewable biocatalysts, the utilization of abundant green, safe, and high energy density fuels, together with the capability of working at modest and biocompatible conditions make EFCs promising as next generation alternative power sources. However, the main challenges (low energy density, relatively low power density, poor operational stability, and limited voltage output) hinder future applications of EFCs. This review aims at exploring the underlying mechanism of EFCs and providing possible practical strategies, methodologies and insights to tackle these issues. First, this review summarizes approaches in achieving high energy densities in EFCs, particularly, employing enzyme cascades for the deep/complete oxidation of fuels. Second, strategies for increasing power densities in EFCs, including increasing enzyme activities, facilitating electron transfers, employing nanomaterials, and designing more efficient enzyme-electrode interfaces, are described. The potential of EFCs/(super)capacitor combination is discussed. Third, the review evaluates a range of strategies for improving the stability of EFCs, including the use of different enzyme immobilization approaches, tuning enzyme properties, designing protective matrixes, and using microbial surface displaying enzymes. Fourth, approaches for the improvement of the cell voltage of EFCs are highlighted. Finally, future developments and a prospective on EFCs are envisioned.

Advanced impedimetric biosensor configuration and assay protocol for glycoprofiling of a prostate oncomarker using Au nanoshells with a magnetic core

In this paper several advances were implemented for glycoprofiling of prostate specific antigen (PSA), what can be applied for better prostate cancer (PCa) diagnostics in the future: 1) application of Au nanoshells with a magnetic core (MP@silica@Au); 2) use of surface plasmons of Au nanoshells with a magnetic core for spontaneous immobilization of zwitterionic molecules via diazonium salt grafting; 3) a double anti-fouling strategy with integration of zwitterionic molecules on Au surface and on MP@silica@Au particles was implemented to resist non-specific protein binding; 4) application of anti-PSA antibody modified Au nanoshells with a magnetic core for enrichment of PSA from a complex matrix of a human serum; 5) direct incubation of anti-PSA modified MP@silica@Au with affinity bound PSA to the lectin modified electrode surface. The electrochemical impedance spectroscopy (EIS) signal was enhanced 43 times integrating Au nanoshells with a magnetic core compared to the biosensor without them. This proof-of-concept study shows that the biosensor could detect PSA down to 1.2 fM and at the same time to glycoprofile such low PSA concentration using a lectin patterned biosensor device. The biosensor offers a recovery index of 108%, when serum sample was spiked with a physiological concentration of PSA (3.5 ng mL^-1).

Cu2+-Modulated in situ growth of quantum dots for split-type photoelectrochemical immunoassay of prostate-specific antigen

A split-type photoelectrochemical immunosensor of PSA was developed using Cu²⁺-dependent catalytic oxidation for inhibiting the in situ growth of CdS QDs.

Landscape Phage: Evolution from Phage Display to Nanobiotechnology

The development of phage engineering technology has led to the construction of a novel type of phage display library-a collection of nanofiber materials with diverse molecular landscapes accommodated on the surface of phage particles. These new nanomaterials, called the "landscape phage", serve as a huge resource of diagnostic/detection probes and versatile construction materials for the preparation of phage-functionalized biosensors and phage-targeted nanomedicines. Landscape-phage-derived probes interact with biological threat agents and generate detectable signals as a part of robust and inexpensive molecular recognition interfaces introduced in mobile detection devices. The use of landscape-phage-based interfaces may greatly improve the sensitivity, selectivity, robustness, and longevity of these devices. In another area of bioengineering, landscape-phage technology has facilitated the development and testing of targeted nanomedicines. The development of high-throughput phage selection methods resulted in the discovery of a variety of cancer cell-associated phages and phage proteins demonstrating natural proficiency to self-assemble into various drug- and gene-targeting nanovehicles. The application of this new "phage-programmed-nanomedicines" concept led to the development of a number of cancer cell-targeting nanomedicine platforms, which demonstrated anticancer efficacy in both in vitro and in vivo experiments. This review was prepared to attract the attention of chemical scientists and bioengineers seeking to develop functionalized nanomaterials and use them in different areas of bioscience, medicine, and engineering.