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Ultrasensitive, selective, and non‐invasive detection of fibrin in human serum is critical for disease diagnosis. So far, the development of high‐performance and ultrasensitive biosensors maintains core challenges for biosensing. Herein, we designed a novel ribbon nanoprobe for ultrasensitive detection of fibrin. The probe contains gold nanoparticles (AuNPs) that can not only link with homing peptide Cys‐Arg‐Glu‐Lys‐Ala (CREKA) to recognize fibrin but also carry long DNA belts to form G‐quadruplex‐based DNAzyme, catalyzing the chemiluminescence of luminol–hydrogen peroxide (H2O2) reaction. Combined with the second amplification procedure of rolling circle amplification (RCA), the assay exhibits excellent sensitivity with a detection limit of 0.04 fmol L−1 fibrin based on the 3‐sigma. Furthermore, the biosensor shows high specificity on fibrin in samples because the structure of antibody‐fibrin‐homing peptide was employed to double recognize fibrin. Altogether, the simple and inexpensive approach may present a great potential for reliable detection of biomarkers. [ABSTRACT FROM AUTHOR]

Homing peptides are widely used to improve the delivery of drugs, imaging agents, and nanoparticles (NPs) to their target sites. Plant virus-based particles represent an emerging class of structurally diverse nanocarriers that are biocompatible, biodegradable, safe, and cost-effective. Similar to synthetic NPs, these particles can be loaded with imaging agents and/or drugs and functionalized with affinity ligands for targeted delivery. Here we report the development of a peptide-guided Tomato Bushy Stunt Virus (TBSV)-based nanocarrier platform for affinity targeting with the C-terminal C-end rule (CendR) peptide, RPARPAR (RPAR). Flow cytometry and confocal microscopy demonstrated that the TBSV-RPAR NPs bind specifically to and internalize in cells positive for the peptide receptor neuropilin-1 (NRP-1). TBSV-RPAR particles loaded with a widely used anticancer anthracycline, doxorubicin, showed selective cytotoxicity on NRP-1-expressing cells. Following systemic administration in mice, RPAR functionalization conferred TBSV particles the ability to accumulate in the lung tissue. Collectively, these studies show the feasibility of the CendR-targeted TBSV platform for the precision delivery of payloads. [ABSTRACT FROM AUTHOR]

Homing peptides are widely used to improve the delivery of drugs, imaging agents, and nanoparticles (NPs) to their target sites. Plant virus-based particles represent an emerging class of structurally diverse nanocarriers that are biocompatible, biodegradable, safe, and cost-effective. Similar to synthetic NPs, these particles can be loaded with imaging agents and/or drugs and functionalized with affinity ligands for targeted delivery. Here we report the development of a peptide-guided Tomato Bushy Stunt Virus (TBSV)-based nanocarrier platform for affinity targeting with the C-terminal C-end rule (CendR) peptide, RPARPAR (RPAR). Flow cytometry and confocal microscopy demonstrated that the TBSV-RPAR NPs bind specifically to and internalize in cells positive for the peptide receptor neuropilin-1 (NRP-1). TBSV-RPAR particles loaded with a widely used anticancer anthracycline, doxorubicin, showed selective cytotoxicity on NRP-1-expressing cells. Following systemic administration in mice, RPAR functionalization conferred TBSV particles the ability to accumulate in the lung tissue. Collectively, these studies show the feasibility of the CendR-targeted TBSV platform for the precision delivery of payloads.

Ultrasensitive, selective, and non-invasive detection of fibrin in human serum is critical for disease diagnosis. So far, the development of high-performance and ultrasensitive biosensors maintains core challenges for biosensing. Herein, we designed a novel ribbon nanoprobe for ultrasensitive detection of fibrin. The probe contains gold nanoparticles (AuNPs) that can not only link with homing peptide Cys-Arg-Glu-Lys-Ala (CREKA) to recognize fibrin but also carry long DNA belts to form G-quadruplex-based DNAzyme, catalyzing the chemiluminescence of luminol-hydrogen peroxide (H 2 O 2 ) reaction. Combined with the second amplification procedure of rolling circle amplification (RCA), the assay exhibits excellent sensitivity with a detection limit of 0.04 fmol L -1 fibrin based on the 3-sigma. Furthermore, the biosensor shows high specificity on fibrin in samples because the structure of antibody-fibrin-homing peptide was employed to double recognize fibrin. Altogether, the simple and inexpensive approach may present a great potential for reliable detection of biomarkers., (© 2024 John Wiley & Sons Ltd.)

A novel, highly sensitive and selective sandwich-like enzyme-linked immunoassay procedure for the detection of fibrin was developed. Firstly the monoclonal anti-fibrinogen which was coated on the surface of microtiter plate can interact with fibrin, and the probe of double-stranded DNA (dsDNA) hemp string containing the homing peptide can secondarily recognize the fibrin. On the other hand, combined with the hybridization chain reaction (HCR), the terminal of dsDNA can be folded to a long G-quadruplex-hemin DNAzyme, which can catalyze luminol–H 2 O 2 system to generate strong chemiluminescence signal. Under the optimal experimental conditions, the assay showed a linear toward fibrin concentration in the range of 0.14–72.5 pM with detection limit of 0.04 pM. Because of high selectivity and ultra-sensitivity, the designed procedure provides great potential for applications in medical diagnosis. • A novel sandwich-like enzyme-linked immunoassay strategy has been developed. • The double recognition of antibody-fibrin-homing peptide improves the selectivity. • The HCR strategy was applied to obtain the dsDNA probe to amplify signal. • The design of long dsDNA hemp string can reduce background signal. [ABSTRACT FROM AUTHOR]

Background: Despite the approval of several medications for pulmonary hypertension, morbidity and mortality are unacceptably high. Systemic hypotension may limit the use of pulmonary hypertension medications., Objectives: This study aimed to assess whether the homing peptide CAR (CARSKNKDC) improves the vasodilatory selectivity of fasudil in the pulmonary circulation or systemic circulation in a porcine pulmonary hypertension model., Materials and Methods: Pulmonary hypertension (to approximately 2/3-3/4 systemic pressure levels) was induced by chronic and acute administration of microspheres in 3 micro Yucatan pigs (mean weight 19.9 kg, mean age 4.3 months). Fasudil (0.3 mg/kg) was administered without and with CAR (1.5 mg/kg), and the effect on aortic (Ao) and right ventricular (RV) pressure was recorded with indwelling catheters., Results: Immediately after fasudil administration, there was a decrease in Ao pressure followed by prompt recovery to baseline. The RV pressure decrease was progressive and sustained. Fasudil alone resulted in a 12% decrease in RV pressure, whereas co-administration of CAR with fasudil resulted in a 22% decrease in RV pressure (p < 0.0001). Fasudil alone caused an average decrease of 34% in the RV/Ao pressure ratio, and fasudil + CAR caused an average decrease of 40% in the RV/Ao pressure ratio (p < 0.0001)., Conclusion: The homing peptide CAR selectively enhanced the acute vasodilatory effects of fasudil on the pulmonary vascular bed in a porcine experimental model of pulmonary hypertension., Competing Interests: All authors, except David Mann, declared no conflicts of interest with respect to the research, authorship, and/or publication of this article. David Mann is a shareholder, patent holder, and employee of Vascular Biosciences., (© 2023 Rothman et al.)

Drugs for metabolic diseases usually require systemic administration and act on multiple tissues, which may produce some unpredictable side effects. There have been many successful studies on targeted drugs, especially antitumor drugs. However, there is still little research on metabolic disease drugs targeting specific tissues. Fibroblast growth factor 1 (FGF1) is a potential therapy for type 2 diabetes (T2D) without the risk of hypoglycemia. However, the major impediment to the clinical application of FGF1 is its mitogenic potential. We previously engineered an FGF1 variant (named FGF1 ΔHBS ) to tune down its mitogenic activity via reducing the heparin-binding ability. However, other notable side effects still remained, including severe appetite inhibition, pathogenic loss of body weight, and increase in fatality rate. In this study, we used AlphaFold2 and PyMOL visualization tools to construct a novel FGF1 ΔHBS conjugate fused with skeletal muscle-targeted (MT) peptide through a flexible peptide linker termed MT-FGF1 ΔHBS . We found that MT-FGF1 ΔHBS specifically homed to skeletal muscle tissue after systemic administration and induced a potent glucose-lowering effect in T2D mice without hypoglycemia. Mechanistically, MT-FGF1 ΔHBS elicits the glucose-lowering effect via AMPK activation to promote the GLUT4 expression and translocation in skeletal muscle cells. Notably, compared with native FGF1 ΔHBS , MT-FGF1 ΔHBS had minimal effects on food intake and body weight and did not induce any hyperplasia in major tissues of both T2D and normal mice, indicating that this muscle-homing protein may be a promising candidate for T2D treatment. Our targeted peptide strategy based on computer-aided structure prediction in this study could be effectively applied for delivering agents to functional tissues to treat metabolic or other diseases, offering enhanced efficacy and reducing systemic off-target side effects.

The triple-negative breast cancer (TNBC) microenvironment makes a feature of aberrant vasculature, high interstitial pressure, and compact extracellular matrix, which combine to reduce the delivery and penetration of therapeutic agents, bringing about incomplete elimination of cancer cells. Herein, employing the tumor penetration strategy of size-shrinkage combined with ligand modification, we constructed a photothermal nanocluster for cascaded deep penetration in tumor parenchyma and efficient eradication of TNBC cells. In our approach, the photothermal agent indocyanine green (ICG) is laded in human serum albumin (HSA), which is cross-linked by a thermally labile azo linker (VA057) and then further modified with a tumor homing/penetrating tLyP-1 peptide (HP), resulting in a TNBC-targeting photothermal-responsive size-switchable albumin nanocluster (ICG@HSA-Azo-HP). Aided by the enhanced permeability and retention effect and guidance of HP, the ca. 149 nm nanoclusters selectively accumulate in the tumor site and then, upon mild irradiation with the 808 nm laser, disintegrate into 11 nm albumin fractions that possess enhanced intratumoral diffusion ability. Meanwhile, HP initiates the CendR pathway among the nutrient-deficient tumor cells and facilitates the transcellular delivery of the nanocluster and its disintegrated fractions for subsequent therapy. By employing this size-shrinkage and peptide-initiated transcytosis strategy, ICG@HSA-Azo-HP possesses excellent penetration capabilities and shows extensive penetration depth in three-dimensional multicellular tumor spheroids after irradiation. Moreover, with a superior photothermal conversion effect, the tumor-penetrating nanocluster can implement effective photothermal therapy throughout the tumor tissue under a second robust irradiation. Both in vivo orthotopic and ectopic TNBC therapy confirmed the efficient tumor inhibition of ICG@HSA-Azo-HP after dual-stage irradiation. The synergistic penetration strategy of on-demanded size-shrinkage and ligand guidance accompanied by clinically feasible NIR irradiation provides a promising approach for deep-penetrating TNBC therapy.

A highly sensitive and specific ELISA-like chemiluminescence method for detection of fibrin has been developed. In the sensing platform, the homing peptide (CREKA), as recognition molecule, which can specially recognize the fibrin on microtiter plate, combined with G-quadruplex-based DNAzyme to form the probe of G-quadruplex-hemin DNAzyme-CREKA. After the sample solution was coated on the plates, the probe was crosslinked with fibrin through the interaction of CREKA and fibrin. Finally, luminol–H 2 O 2 chemiluminesecence (CL) reaction was exploited for quantitative analysis of fibrin. The liner range for fibrin detection was from 0.112 pmol L−1 to 5.6 pmol L−1 with the detection limit of fibrin as low as 0.04 pmol L−1, based on a signal-to-noise ratio (S/N) of 3. Furthermore, on the basis of the high amplification efficiency of the rolling circle amplification (RCA) reaction, the method enabled to analyze fibrin with a detection limit corresponding to 0.06 fmol L−1, whose sensitivity increased 3 orders of magnitude than that of above method in the absence of RCA reaction. In particular, combined with the separation and washing steps of ELISA, the proposed method possessed higher selectivity, high-throughput and low cost, which shows promise for applications in clinical diagnosis. [Display omitted] • Combined with RCA process, A highly sensitive and specific ELISA-like chemiluminescence method for detection of fibrin has been developed. • The proposed method possessed high selectivity, high-throughput and low cost, since the separation and washing steps of ELISA were introduced. • The novel ELISA-like chemiluminescence method may open a perspective, which shows promise for applications in clinical diagnosis. [ABSTRACT FROM AUTHOR]

In vivo peptide-phage display is an unbiased technique for mapping of the vascular diversity and identification of homing peptides. This chapter is intended to serve as a structured practical guide to execute in vivo T7 phage biopanning and data analysis experiments. We discuss experimental designs and protocols with emphasis on application of high-throughput sequencing-based technologies for streamlined in vivo biopanning and validation of homing peptides., (© 2022. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)