Peptide Carrier Research Articles

Tailoring Uptake Efficacy of HSV-1 gD Tailoring Uptake Efficacy of Hsv-1 GD Derived Carrier Peptides

Regions of the Herpes simplex virus-1 (HSV-1) glycoprotein D (gD) were chosen to design carrier peptides based on the known tertiary structure of the virus entry receptor complexes. These complexes consist of the following: HSV-1 gD–nectin-1 and HSV-1 gD–herpesvirus entry mediator (HVEM). Three sets of peptides were synthesised with sequences covering the (i) N-terminal HVEM- and nectin-1 binding region -5–42, (ii) the 181–216 medium region containing nectin-1 binding sequences and (iii) the C-terminal nectin-1 binding region 214–255. The carrier candidates were prepared with acetylated and 5(6)-carboxyfluorescein labelled N-termini. The peptides were chemically characterised and their conformational features in solution were also determined. In vitro internalisation profile and intracellular localisation were evaluated on SH-SY5Y neuroblastoma cells. Peptide originated from the C-terminal region 224–247 of the HSV-1 gD showed remarkable internalisation compared to the other peptides with low to moderate entry. Electronic circular dichroism secondary structure studies of the peptides revealed that the most effectively internalised peptides exhibit high helical propensity at increasing TFE concentrations. We proved that oligopeptides derived from the nectin-1 binding region are promising candidates—with possibility of Lys237Arg and/or Trp241Phe substitutions—for side-reaction free conjugation of bioactive compounds—drugs or gene therapy agents—as cargos.

Engineered M13 Peptide Carrier Promotes Angiogenic Potential of Patient-Derived Human Cardiac Progenitor Cells and In Vivo Engraftment.

Despite promising advances in stem cell-based therapy, the treatment of ischemic cardiovascular diseases remains a big challenge due to both the insufficient in vivo viability of transplanted cells and poor angiogenic potential of stem cells. The goal of this study was to develop therapeutic human cardiac progenitor cells (hCPCs) for ischemic cardiovascular diseases with a novel M13 peptide carrier. In this study, an engineered M13 peptide carrier was successfully generated using a QuikChange Kit. The cellular function of M13 peptide carrier-treated hCPCs was assessed using a tube formation assay and scratch wound healing assay. The in vivo engraftment and cell survival bioactivities of transplanted cells were demonstrated by immunohistochemistry after hCPC transplantation into a myocardial infarction animal model. The engineered M13RGD+SDKP peptide carrier, which expressed RGD peptide on PIII site and SDKP peptide on PVIII site, did not affect morphologic change and proliferation ability in hCPCs. In contrast, hCPCs treated with M13RGD+SDKP showed enhanced angiogenic capacity, including tube formation and migration capacity. Moreover, transplanted hCPCs with M13RGD+SDKP were engrafted into the ischemic region and promoted in vivo cell survival. Our present data provides a promising protocol for CPC-based cell therapy via short-term cell priming of hCPCs with engineered M13RGD+SDKP before cell transplantation for treatment of cardiovascular disease.

Aiming at the tumor-specific accumulation of MGMT-inhibitors: First description of a synthetic strategy towards inhibitor-peptide conjugates

In the therapy of cancer, alkylating agents are an efficient and often-used substance class. However, cells can repair the resulting alkyl modifications in the O6-position of guanine using the repair protein methylguanine methyltransferase (MGMT), giving rise to resistance and inefficient therapy. A possibility to overcome this resistance is the use of MGMT inhibitors as adjuvants to alkylating therapies. However, MGMT inhibitors also sensitize healthy cells towards alkylating therapies. A strategy to circumvent this is the development of tumor-specific inhibitors which could be based on peptidic ligands as carriers. Such constructs would enable a receptor-specific uptake into tumors. Furthermore, the MGMT inhibitors could be adapted to the respective tumor entity by changing the peptide carrier. However, no peptide-based tumor-specific MGMT inhibitors were described so far. Thus, we have developed a synthetic strategy to obtain covalent conjugates of receptor-specific peptides and O6-benzylguanine derivatives. As model compounds, the MGMT inhibitor O6-(3-bromobenzyl)guanine and the receptor-specific peptides c(RGDfK), TATE, PESIN, neurotensin-2656 and minigastrin-9 were chosen and successfully assembled to obtain potentially tumor-specific MGMT inhibitors. Both, the O6-(3-bromobenzyl)guanine as well as the peptide derivatives are easily replaceable during the syntheses to tailor peptide-based bioconjugates adaptable to the specific tumor entity.

Heterologous peptide display on chromatin nanofibers: A new strategy for peptide vaccines

Chromatin organization starts from a “beads-on-a string” 10 nm fiber, a basic nucleosomal structure consisting of DNA and core histones. Given its regular nucleosome array on DNA backbone where N-terminal tails of each histone are exposed on the surface of chromatin fiber, we hypothesized that chromatin can be utilized as a heterologous peptide carrier to elicit a peptide-specific immune response. The plasmid DNA containing the Widom’s clone 601 sequence and the recombinant chimeric histones containing the peptide derived from ras oncogene (G12V) were used to assemble the chromatin fiber in vitro. The immunogenicity of the assembled chromatin was tested in mice as a single vaccine component or formulated with adjuvants. G12V tagged-chromatin co-administered with adjuvants induced higher antibody responses against the G12V peptide than vaccination with adjuvant alone, while chimeric histones did not generate a significant antibody response. Interestingly, splenocytes from mice vaccinated with the G12V tagged-chromatin vaccine did not generate significant antigen-specific cytokine responses. Our studies suggest that chromatin can be utilized as an effective carrier of antigenic peptides for inducing specific antibody responses.

Isolation and characterization of new human carrier peptides from two important vaccine immunogens

In the preparation of glycoconjugate vaccines in clinical practice, two highly immunogenic carrier proteins, CRM197 and tetanus toxoid (TT), are predominantly conjugated with the capsular polysaccharides (CPSs) of bacterial pathogens. In addition, TT has long been used as an effective vaccine to prevent tetanus. While these carrier proteins play an important role in immunogenicity and vaccine design alike, their defined human major histocompatibility complex class II (MHCII) T cell epitopes are inadequately characterized. In this current work, we use mass spectrometry to identify the peptides from these carrier proteins that are naturally processed and presented by human B cells via MHCII pathway. The MHCII-presented peptides are screened for their T cell stimulation using primary CD4+ T cells from four healthy adult donors. These combined methods reveal a subset of eleven CD4+ T cell epitopes that proliferate and stimulate human T cells with diverse MHCII allelic repertoire. Six of these peptides stand out as potential immunodominant epitopes by responding in three or more donors. Additionally, we provide evidence of these natural epitopes eliciting more significant T cell responses in donors than previously published TT peptides selected from T cell epitope screening. This study serves toward understanding carrier protein immune responses and thus enables the use of these peptides in developing novel knowledge-based vaccines to combat persisting problems in glycoconjugate vaccine design.

The targeted LHRH analog AEZS-108 alters expression of genes related to angiogenesis and development of metastasis in uveal melanoma.

Uveal melanoma (UM) is the most common malignant tumor of the eye. Recently, we have established that 46% of UM specimens express LHRH receptors. This finding supports the idea of a LHRH receptor-targeted therapy of UM patients. Cytotoxic analog of LHRH, AEZS-108 exhibits effective anti-cancer activity in LHRH-receptor positive cancers. AEZS-108 is a hybrid molecule, composed of a synthetic peptide carrier and the cytotoxic doxorubicin (DOX). In the present study, we investigated AEZS-108 induced cytotoxicity and the altered mRNA expression profile of regulatory factors related to angiogenesis and metastasis in LHRH receptor positive OCM3 cells. Our results show that AEZS-108 upregulates the expression of MASPIN/SERPINB5 tumor suppressor gene, which is downregulated in normal uvea and UM specimens independently from the LHRH receptor-ligand interaction. AEZS-108 also substantially downregulates hypoxia-inducible factor 1 alpha (HIF1A) expression. In order to investigate the mechanism of the induction of MASPIN by AEZS-108, OCM3 cells were treated with free DOX, D-Lys6 LHRH analog, or AEZS-108. qRT- PCR analysis revealed in OCM3 cells that AEZS-108 is a more potent inducer of MASPIN than free DOX. In conclusion, we show for the first time that AEZS-108 has a major impact in the regulation of angiogenesis thus plays a potential role in tumor suppression. Taken together, our results support the development of novel therapeutic strategies for UM focusing on LHRH receptors.

Nanodiamonds: unique nanoparticles for use in biomedicine and biotechnology

Nanodiamonds are ultra-fine diamond particles, which due to their nano-scale size, unique physico-chemical properties, and a large ratio of easily chemically modifiable surface to volume, are of interest to biologists, chemists and physicists. This work is a review of the literature on their preparation, properties and perspectives related to the possibility of their use in biomedical sciences. The high biocompatibility of nanodiamonds, confirmed by a number of in vivo and in vitro studies, distinguishes them from other nanoparticles and allows their use as a neutral system for transporting biologically active compounds. Such nanoparticles can be used as carriers of peptides, proteins, nucleic acids, drugs or other synthetic compounds that will cause the intended biological effect in the body, in bioimaging and tissue engineering. Promising results of studies on different biological models suggest practical applications of nanotechnological solutions based on nanodiamonds.

FDM-printed pH-responsive capsules for the oral delivery of a model macromolecular dye

To this day, the oral delivery of biomacromolecules remains a major developmentally-oriented challenge. A combinatorial approach was followed at this study, to formulate an efficient carrier for the in vitro delivery of a model macromolecule, fluorescein isothiocyanate–dextran 4 kDa (FD4). The model macromolecule was formulated in a self-assembling peptide hydrogel (ac-(RADA)4-CONH2), prior to deposition in a hydroxypropyl methylcellulose-phthalate (HPMCP)-based 3D-printed capsule. Loading of FD4 was investigated for potential alterations on the structural (AFM) and gelling properties of the peptide carrier. Thermal analysis and morphological properties of the 3D-printed capsules were assessed by TGA, DSC and microscopy studies. For the peptide hydrogel, similar release profiles of FD4 were recorded in simulated gastric fluid pH 1.2 and phosphate buffer saline pH 7.4, indicating the need for a structural barrier, to protect the peptide carrier from the acidic environment of the stomach. The pH responsive character of the HPMCP-based capsule was evidenced in the release profiles of FD4 in a sequence of release media, i.e. simulated gastric fluid pH 1.2, simulated intestinal fluid pH 6.8 and phosphate buffer saline pH 7.4. The results supported the combinatorial formulation approach as a promising system for the efficient oral delivery of biomacromolecules.

Recent Advances in Protein and Peptide Drug Delivery

Peptides and proteins have great therapeutic potential. Proteins and peptides may be administered for therapeutic effects at comparatively low doses because of their relatively specific mode of action. For several chronic conditions such as cancer, hepatitis, diabetes, rheumatoid arthritis and leukaemia, this potent therapy is indicated. While the peptide and protein therapeutic market has developed significantly over the past decades, their use has been limited by delivery. Most are currently delivered intravenously or subcutaneously due to degradation and limited absorption in the gastrointestinal tract, although oral delivery is preferred. In order to facilitate the oral peptide delivery, absorption enhancers, enzyme inhibitors, carrier systems and stability enhancers are therefore being studied. Additionally, the delivery of transdermal peptides avoids gastrointestinal tract problems but also faces absorption limitations. Injections (i.e. intravenous, intramuscular, or subcutaneous route) remain the most common means of administering these protein and peptide drugs until recently. The oral, buccal, intranasal, pulmonary, transdermal, ocular and rectal routes that have been tried with varying degrees of success. This review discusses oral and transdermal peptide drug delivery, focusing on barriers and solutions to absorption and recent advances are discussed.

Cys-Flanked Cationic Peptides For Cell Delivery of the Herpes Simplex Virus Thymidine Kinase Gene for Suicide Gene Therapy of Uterine Leiomyoma

Uterine leiomyoma (UL) is the most common benign tumor in women of reproductive age. Gene therapy using suicidal genes appears to be a promising approach for UL treatment. One of key factors for success of gene therapy is the right choice of genetic construct carrier. A promising group of non-viral carriers for cell delivery of expression vectors is cationic Cys-flanked peptides which form tight complexes with DNA due to electrostatic interactions and the presence of interpeptide disulfide bonds. The paper reports a comparative study of the physico-chemical, toxic, and transfectional properties of the DNA-peptide complexes obtained by matrix polymerization or oxidative polycondensation of Cys-flanked peptides using the chain growth terminator 2-amino ethanethiol. We have demonstrated the therapeutic effect of the delivery of the pPTK-1 plasmid carrying the herpes simplex virus type 1 (HSV-1) thymidine kinase gene into PANC-1, and HEK-293T cell culture as well as into primary UL cells. It has been shown that the carriers obtained by oxidative polycondensation transform primary UL cells more efficiently than those produced by matrix polymerization. Treatment with ganciclovir resulted in the death of up to 40% of UL cells transfected with the pPTK-1 plasmid. The perspectives of use of the polyR6 carrier produced by oxidative polycondensation as a tool for the development of modular peptide carriers for the purposes of UL gene therapy were discussed.

Cellular binding analysis of recombinant hybrid heteropolymer of camel hepcidin and human ferritin H chain. The unexpected human H-ferritin binding to J774 murine macrophage cells.

Ferritin is a molecule with enormous potentiality in biotechnology that have been already used to encapsulate molecules, as contrast in magnetic resonance imaging and to carry epitopes. We proposed to use it to carry another key protein of iron metabolism, hepcidin that is a small hormone peptide that control systemic iron homeostasis. In this work, we purified the previously produced camel hepcidin and human H-ferritin heteropolymer (HepcH-FTH) and to monitor its binding capability toward J744 cell line in presence or absence of ferric ammonium citrate. Fused camel hepcidin and human H-ferritin monomer (HepcH) as well as the assembled HepcH-FTH heteropolymer (ratio 1:5) was easily purified by a one-step purification using size exclusion chromatography. SDS-PAGE electrophoresis of HepcH, purified from soluble and insoluble fractions, showed a single band of 24kDa with an estimated purity of at least 90%. The purification yields of HepcH from the soluble and insoluble fractions was, respectively, of about 6.80 and 2mg/L of bacterial culture. Time curse cellular binding assays of HepcH-FTH revealed its great potential to bind the J774 cells after 15min of incubation. Furthermore, HepcH-FTH was able to degrade ferroportin, the unique hepcidin receptor, even after 30min of incubation with J774 cells treated with 100µM ferric ammonium citrate. In conclusion, we proposed ferritin as a peptide carrier to promote the association of the hybrid HepcH-FTH nanoparticle with a particular type of cell for therapeutic or diagnostic.

In Vitro Digestion of Microcapsule Carriers for Oral Delivery of Bioactive Compounds for Diabetes Treatment and Their Inhibitory Effect on the DPP-4 Enzyme

Empty microcapsules, originally designed as carriers of bioactive peptides, were prepared by the combined method of a double-emulsion complex with coacervation spray drying and were subjected to an in-vitro digestion process, producing peptides from the whey protein contained in the microcapsule walls. The inhibitory effect of the enzyme dipeptidyl peptidase-4 (DPP-4) and modulation of the insulin receptor of hydrolyzed microcapsules were evaluated. The hydrolysate of the microcapsules was subjected to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) analysis, showing the presence of low-molecular-weight peptidic compounds, which apparently were responsible for the DPP-4 inhibitory effect. Fluorescence analysis showed that the effect of the hydrolyzed microcapsules on the insulin receptor was 40% that of insulin. The inhibition of DPP-4 was 54.7%. This work demonstrated that empty microcapsules initially designed as carriers of functional peptides also have the capability to inhibit DPP-4 and modulate insulin receptors by themselves.

Copper(I) complexes with phosphines P(p-OCH3-Ph)2CH2OH and P(p-OCH3-Ph)2CH2SarGly. Synthesis, multimodal DNA interactions, and prooxidative and in vitro antiproliferative activity

Phosphonium salt (p-OCH3-Ph)2P(CH2OH)2Cl (MPOHC), derived phosphine ligands without and with SarGly (Sarcosine-Glycine) peptide carrier P(p-OCH3-Ph)2CH2OH (MPOH) and P(p-OCH3-Ph)2CH2SarGly (MPSG), respectively, and two copper(I) complexes [Cu(I)(dmp)(MPOH)] (1-MPOH; dmp = (2,9-dimethyl-1,10-phenanthroline)) and [Cu(I)(dmp)(MPSG)] (1-MPSG) were synthesized. The resulting compounds were characterized by elemental analysis, 1D and 2D NMR and UV–Vis absorption spectroscopies, mass spectrometry, cyclic voltammetry and by X-ray diffraction analysis. Cytotoxicity of all compounds was evaluated in vitro against colon, lung, breast, pancreatic, prostate tumor cell lines, as well as towards non-tumor cell lines: lung, kidney and keratinocyte. Stable in biological medium in the presence of atmospheric oxygen, Cu(I) complexes exerted a cytotoxic effect higher than that elicited by cisplatin against tested cancer cell lines. The introduction of methoxy group onto the phenyl rings of the phosphine ligand coordinated to the copper(I) ion resulted in a relevant increase of cytotoxicity in the case of breast, pancreatic and prostate tumor cell lines in vitro. Attachment of a peptide carrier significantly increased the selectivity towards cancer cells. Fluorescence spectroscopic data (calf thymus DNA: CT-DNA) titration), together with analysis of DNA fragmentation (gel electrophoresis) and molecular docking provided evidence for the multimodal interaction of copper compounds with DNA and showed their unusual low genotoxicity. Additionally, copper complexes were able to generate reactive oxygen species as a result of redox processes, proved by fluorescence spectroscopy and cyclic voltamperometry.

Suppressing miR-21 activity in tumor-associated macrophages promotes an antitumor immune response.

microRNA-21 (miR-21) is the most commonly upregulated miRNA in solid tumors. This cancer-associated microRNA (oncomiR) regulates various downstream effectors associated with tumor pathogenesis during all stages of carcinogenesis. In this study, we analyzed the function of miR-21 in noncancer cells of the tumor microenvironment to further evaluate its contribution to tumor progression. We report that the expression of miR-21 in cells of the tumor immune infiltrate, and in particular in macrophages, was responsible for promoting tumor growth. Absence of miR-21 expression in tumor- associated macrophages (TAMs), caused a global rewiring of their transcriptional regulatory network that was skewed toward a proinflammatory angiostatic phenotype. This promoted an antitumoral immune response characterized by a macrophage-mediated improvement of cytotoxic T-cell responses through the induction of cytokines and chemokines, including IL-12 and C-X-C motif chemokine 10. These effects translated to a reduction in tumor neovascularization and an induction of tumor cell death that led to decreased tumor growth. Additionally, using the carrier peptide pH (low) insertion peptide, we were able to target miR-21 in TAMs, which decreased tumor growth even under conditions where miR-21 expression was deficient in cancer cells. Consequently, miR-21 inhibition in TAMs induced an angiostatic and immunostimulatory activation with potential therapeutic implications.

Endothelialization of Titanium Surfaces by Bioinspired Cell Adhesion Peptide Coatings.

Common interventional therapies for cardiovascular occlusive diseases, such as the implantation of stents, are at risk of complications like thrombosis or restenosis. Drug-eluting stents have improved patency but simultaneously worsen the endothelialization of the implant. Here, we present a novel peptide coating derived from three proteins of the extracellular matrix named fibronectin, laminin, and elastin. Their active sequences RGD, SIKVAV, and VGVAPG were immobilized onto titanium surfaces by a carrier peptide containing l-3,4-dihydroxyphenylalanine (DOPA). Simultaneous functionalization of the carrier peptide with cyclic c[RGDfK] and SIKVAV had the most potent influence on adhesion, proliferation, viability, and angiogenesis of endothelial cells. By presentation of two adhesion peptides in one molecule, a synergistic enhancement of cell-surface interactions was achieved. Overall, this work clearly demonstrates the advantages of spatially defined peptide coatings for the endothelialization of titanium and thus describes a promising approach for the coating of stents.

Optimization of PVA-Arabic Gum–Honey-based Electrospun Nanofibers as Candidate Carrier for Peptide and Protein Delivery

Nanofibers dressing exhibit several advantageous characteristics for accelerating wound healing, such as its similar structure to the extracellular matrix (ECM), high surface area/volume ratio, high porosity and high loading capacity of drug. The nanofibers dressing which were prepared by the electrospinning technique using combination of synthetic and natural polymer excipients capable of fulfilling the ideal wound dressing criteria. This study aimed to develop nanofibers dressing prepared from polyvinyl alcohol (PVA), Arabic gum (GA) and honey by electrospinning method. This study focused on the effect of electrospinning parameters and the morphology of electrospun nanofibers of the blended solutions made from PVA (9% w/v) – GA (1% w/v) and honey (at varied concentrations of 0;1;3% w/v) with or without Triton X-100 (0.05% v/v). The effect of varied process parameters such as voltage and flow rate in electrospinning was also investigated. The blended solutions with the various concentration of honey at 0;1;3% w/v and Triton X-100 were named as FAt, FBt, and FCt, respectively, while the blended solutions without Triton X-100, were named as FA, FB, and FC. The optimum electrospining parameter were 18 KV and 5 µl/minute for FAt, FBt, and FCt; and 20 KV and 10 µl/minute for FA, FB, and FC. Electrospun nanofibers of FAt, FBt, FCt showed smoother and more uniform fibers in comparison to the nanofibers FA, FB, and FC. The average nanofibers diameter of FAt, FBt, FCt were 244±45; 266±45; 283±57 nm, respectively, while the average nanofibers diameter of FA, FB, FC was 406±140, 457±168, 594±204 nm, respectively. Higher concentration of honey increased the diameters of nanofibers. The average nanofibers diameter of FAt, FBt, and FCt were within nanoscale in range of the ECM (50-500 nm), which were suitable for accelerating wound healing. Therefore, this study indicated that PVA-GA-honey nanofibers dressing is suitable to be further developed as carrier for growth factors.

The Nanoformulations of Curcumin for Cancer Therapy: New Perspectives

Curcumin is a natural yellow phenolic compound that is located in many types of herbs, especially Curcuma Lana (Turmeric). It is a natural anti-oxidant and has shown many pharmaceutical activities in the preclinical and clinical studies such as antioxidant, anti-microbial, anti-cancer and anti-alzheimer disease effects. In addition, curcumin was proven to be anti-diabetic, hepatoprotective, neuroprotective and anti-rheumatic and it also protects against thrombosis and myocardial infarction. The major limitation to the use of curcumin in clinical practice is its very low oral bioavailability. Therefore, many technologies have been developed and implemented to overcome this limitation. In this review, we discussed the latest perspectives regarding the design and development of nano-sized systems for the anti-diabetic agent curcumin, including liposomes, polymeric nanoparticles, micro-conjugates, micelles, peptide carriers, solid dispersions, cyclodextrins, emulsions and lipid nanopeptides and their role as a promising hope for cancer therapy.

Overcharging Effect in Electrospray Ionization Mass Spectra of Daunomycin-Tuftsin Bioconjugates.

Peptide-based small molecule drug conjugates for targeted tumor therapy are currently in the focus of intensive research. Anthracyclines, like daunomycin, are commonly used anticancer drug molecules and are also often applied in peptide-drug conjugates. However, lability of the O-glycosidic bond during electrospray ionization mass spectrometric analysis hinders the analytical characterization of the constructs. “Overprotonation” can occur if daunomycin is linked to positively charged peptide carriers, like tuftsin derivatives. In these molecules, the high number of positive charges enhances the in-source fragmentation significantly, leading to complex mass spectra composed of mainly fragment ions. Therefore, we investigated different novel tuftsin-daunomycin conjugates to find an appropriate condition for mass spectrometric detection. Our results showed that shifting the charge states to lower charges helped to keep ions intact. In this way, a clear spectrum could be obtained containing intact protonated molecules only. Shifting of the protonation states to lower charges could be achieved with the use of appropriate neutral volatile buffers and with tuning the ion source parameters.

Electrochemically synthesized γ-Fe2O3 nanoparticles as peptide carriers and sensitive and reproducible SERS biosensors. Comparison of adsorption on γ-Fe2O3 versus Fe

Nontoxic to human γ-iron(III) oxide nanoparticles (γ-Fe2O3NPs) with ferrimagnetic and semiconductor properties, surface-functionalized with a peptide, can be useful as biosensors, drug-carriers, and therapeutic agents in MRI and hyperthermia. Surface-functionalized γ-Fe2O3NPs can protect tissue from damage caused by generation and attack of OH free radicals resulting from the exposure of Fe2O3 to visible light. Reducing the side effects of conventional therapy makes Fe2O3 a promising tool for the treatment of cancer. γ-Fe2O3NPs were synthesized in surfactant/ions-free aqueous solution on a new synthetic route, allowing control the size and morphology of the nanoparticles. γ-Fe2O3NPs were characterized by UV–vis, SEM-EDS, FTIR-ATR, Raman, XPS, XRD, Mössbauer, and DLS methods. It was shown that the aged nanoparticles were highly pure (γ-phase), well-crystallized, and had a spherical shape of an average diameter of 77 nm. γ-Fe2O3NPs were tested for their ability (i.) to adsorb Bombesin which occurs in the human body fluids and is known to induce tumor cell growth and (ii.) to promote the SERS effect. The SERS spectra on γ-Fe2O3 were compared to the SERS spectra on the α-Fe surface. The analysis was supported by SERS data for selected amino acids and BN immobilized on Cu, Au, Ag, Au@SiO2, and Ti.

Native protein delivery into rice callus using ionic complexes of protein and cell-penetrating peptides.

Direct protein delivery into intact plants remains a challenge for the agricultural and plant science fields. Cell-penetrating peptide (CPP)-mediated protein delivery requires the binding of CPPs to a protein to carry the protein into the cell through the cell wall and lipid bilayer. Thus, we prepared ionic complexes of a CPP-containing carrier peptide and a cargo protein, namely, Citrine yellow fluorescent protein, and subsequently studied their physicochemical properties. Two types of carrier peptides, BP100(KH)9 and BP100CH7, were investigated for delivery efficiency into rice callus. Both BP100(KH)9 and BP100CH7 successfully introduced Citrine protein into rice callus cells under pressure and vacuum treatment. Moreover, delivery efficiency varied at different growth stages of rice callus; 5-day rice callus was a more efficient recipient for Citrine than 21-day callus.