Polymer-antibody fragment conjugates for biomedical applications

Antibody–Biopolymer Conjugates in Oncology: A Review

Cancer is one of the most prevalent diseases and affects a large proportion of the population worldwide. Conventional treatments in the management include chemotherapy, radiotherapy, and surgery. Although being well-accepted, they have many lacunas in the form of severe side effect resulting from lack of targeted delivery. Antibody biopolymer conjugates are a novel method which is an add-on to older methods of immunization. It is used in various diseases and disorders. It ensures the targeted delivery of molecules to increase its efficacy and reduce unwanted effects of the molecule/drug to normal cells. It shows miraculous results in the treatment and management of several cancers even in advanced stages. Herein, we present the chemistry between biopolymer and antibody, their effects on cancer as well as the basic differences between antibody–drug conjugates and antibody–biopolymer conjugates.

Advances in antibody nanoconjugates for diagnosis and therapy: A review of recent studies and trends

Nowadays, the targeted imaging probe and drug delivery systems are the novel breakthrough area in the nanomedicine and treatment of various diseases. Conjugation of monoclonal antibodies and their fragments on nanoparticles (NPs) have a remarkable impact on personalized medicine, such that it provides specific internalization and accumulation in the tumor microenvironment. Targeted imaging and early detection of cancer is presumably the strong participant to a diminution in mortality and recurrence of cancer disease that will be the next generation of the imaging device in clinical application. These intelligent delivery systems can deliver therapeutic agents that target cancerous tissue with minimal side effects and a wide therapeutic window. Overall, the linkage between the antibody and NPs is a critical subject and requires precise design and development. The attachment of antibody nanoconjugates (Ab-NCs) on the antigen surface shouldn't affect the function of the antibody-antigen binding. Also, the stability of the antibody nanoconjugates in blood circulation is concerned to avoid the release of drug in non-targeted regions and the possible for specific toxicity while disposal to the desired site. Here, we update the recent progress of Ab-NCs to improve early detection and cancer therapy.

Biological responses to physicochemical properties of biomaterial surface

Biomedical scientists use chemistry-driven processes found in nature as an inspiration to design biomaterials as promising diagnostic tools, therapeutic solutions, or tissue substitutes. While substantial consideration is devoted to the design and validation of biomaterials, the nature of their interactions with the surrounding biological microenvironment is commonly neglected. This gap of knowledge could be owing to our poor understanding of biochemical signaling pathways, lack of reliable techniques for designing biomaterials with optimal physicochemical properties, and/or poor stability of biomaterial properties after implantation. The success of host responses to biomaterials, known as biocompatibility, depends on chemical principles as the root of both cell signaling pathways in the body and how the biomaterial surface is designed. Most of the current review papers have discussed chemical engineering and biological principles of designing biomaterials as separate topics, which has resulted in neglecting the main role of chemistry in this field. In this review, we discuss biocompatibility in the context of chemistry, what it is and how to assess it, while describing contributions from both biochemical cues and biomaterials as well as the means of harmonizing them. We address both biochemical signal-transduction pathways and engineering principles of designing a biomaterial with an emphasis on its surface physicochemistry. As we aim to show the role of chemistry in the crosstalk between the surface physicochemical properties and body responses, we concisely highlight the main biochemical signal-transduction pathways involved in the biocompatibility complex. Finally, we discuss the progress and challenges associated with the current strategies used for improving the chemical and physical interactions between cells and biomaterial surface.

Ligand targeting and peptide functionalized polymers as non-viral carriers for gene therapy

Ligand targeting and peptide functionalized polymers serve as gene carriers for efficient gene delivery.

Design, development and evaluation of PEGylated rhGH with preserving its bioactivity at highest level after modification

Modification of recombinant proteins with polyethylene-glycol (PEG) can improve their pharmacokinetic properties, although their bioactivity may be reduced after PEGylation due to structural changes. In this study, simultaneous optimization of PEGylation efficiency and preserved bioactivity of recombinant human growth hormone (rhGH) was investigated. In this regard, experiments were designed by the response surface methodology (RSM)-central composite design (CCD) utilizing design expert software. Under the obtained optimum conditions of 6.73 molar ratio of PEG to protein and pH 7.71 as the main factors affect the process, 54% PEGylation efficiency and 63% preserved bioactivity can be achieved. Based on the ANOVA table, model F-values equal to 31.16 and 20.8 for PEGylation efficiency and preserved bioactivity, respectively, demonstrated the validity and importance of the models. High performance liquid chromatography (HPLC) and gel electrophorese analyses verified the purity of the PEGylated form of rhGH. Findings showed that the modified protein would be stable for six months at 4 °C. In vitro cell growth assessments revealed Nb2-11 cell proliferation during 48 h, although proliferation rate decrease with the increase of PEGylated rhGH concentration. Half-life prolongation in serum observed for PEGylated form in comparison with the non-modified one on in vivo. In overall, the results are promising for the utilization of the PEGylated form of rhGH for the treatment of human growth deficiency after further investigations.

Polymer nanoparticles for the intravenous delivery of anticancer drugs: the checkpoints on the road from the synthesis to clinical translation

In this review article we discuss some of the key aspects concerning the development of a polymer-based nanoparticle formulation for intravenous drug delivery. Since numerous preparations fail before and during clinical trials, our aim is to emphasize the main issues that a nanocarrier has to face once injected into the body. These include biocompatibility and toxicity, drug loading and release, nanoparticle storage and stability, biodistribution, selectivity towards the target organs or tissues, internalization in cells and biodegradability. They represent the main checkpoints to define a polymer-based formulation as safe and effective. Indeed, this review is intended to provide guidelines to be followed in the early development of a new nanotherapeutic to hopefully increase the success rate of polymer-based formulations entering clinical trials. The corresponding requirements and characteristics are discussed in the context of some relevant case studies taken from the literature and mainly related to the delivery of lipophilic anticancer therapeutics.

Temperature-regulated protein adsorption on a PNIPAm layer

In immunosensors, antibody orientation is a key factor that determines the sensitivity of a device. To date much effort has been devoted to exploring strategies for the direct control of the orientation of antibodies immobilized on a bioactive surface, but less attention has been paid to controlling the orientation of intermediate proteins (though usually used when immobilizing antibodies), which may greatly limit the sensitivity of immunological activities. Therefore, it is of great significance to seek novel methods for controlling protein orientation. Here, we design a new strategy for controlling protein orientation. The main idea is to bind proteins to a ligand-functionalized poly(N-isopropylacrylamide) (PNIPAm) layer, and then the protein orientation can be mediated by environmental temperature. The theory predicts that the protein orientation can show unexpected triple-thermo-responsive behavior. Based on the fraction of ligand adsorbed by the protein, the reponsive behavior can be either complete adsorption or partial adsorption, which is determind by the polymer's surface coverage and the protein's properties. We expect that the present strategy can enrich the methods for controlling intermediate protein orientation and can guide the design of novel immunosensors with superior sensitivity.

Antioxidant activity and controlled drug delivery potential of tragacanth gum-cl- poly (lactic acid-co-itaconic acid) hydrogel

Tragacanth gum-cl-poly (lactic acid-co-itaconic acid) (TG-cl-p(LA-co-IA)) hydrogel is synthesized through graft copolymerization reaction using microwave assisted technique. The synthesized hydrogel was characterised using various analytical and characterization techniques such as FTIR, FESEM, XRD, TGA, TEM and SEM. It was observed that, the maximum percentage swelling (P_s) of the hydrogel was 311.61% after 6h at room temperature and 298.06% after 3h at 60°C and TG-cl-p(LA-co-IA) exhibited highest Amoxicillin loading (73%) in double distilled waterafter 24h. From the controlled release studies, it was evident that maximum drug release of about 96% took place at pH 2.2=after 6h. The synthesized hydrogel also showed mild antioxidant properties and 43.85% of free radical scavenging was occurred at a concentration of 640μg/mL and hence it can be effectively used to reduce the oxidative stresses. In addition to this, the antibacterial studies also showed that it is more effective against S. aureus.

Adding Functions to Biomaterial Surfaces through Protein Incorporation

The concept of biomaterials has evolved from one of inert mechanical supports with a long-term, biologically inactive role in the body into complex matrices that exhibit selective cell binding, promote proliferation and matrix production, and may ultimately become replaced by newly generated tissues in vivo. Functionalization of material surfaces with biomolecules is critical to their ability to evade immunorecognition, interact productively with surrounding tissues and extracellular matrix, and avoid bacterial colonization. Antibody molecules and their derived fragments are commonly immobilized on materials to mediate coating with specific cell types in fields such as stent endothelialization and drug delivery. The incorporation of growth factors into biomaterials has found application in promoting and accelerating bone formation in osteogenerative and related applications. Peptides and extracellular matrix proteins can impart biomolecule- and cell-specificities to materials while antimicrobial peptides have found roles in preventing biofilm formation on devices and implants. In this progress report, we detail developments in the use of diverse proteins and peptides to modify the surfaces of hard biomaterials in vivo and in vitro. Chemical approaches to immobilizing active biomolecules are presented, as well as platform technologies for isolation or generation of natural or synthetic molecules suitable for biomaterial functionalization.

Protein–polymer conjugates prepared via host–guest interactions: effects of the conjugation site, polymer type and molecular weight on protein activity

Protein–polymer conjugates are prepared via host–guest interactions and the effects of various parameters on protein activity are investigated.

Synthetically Modified Viral Capsids as Versatile Carriers for Use in Antibody-Based Cell Targeting

The present study describes an efficient and reliable method for the preparation of MS2 viral capsids that are synthetically modified with antibodies using a rapid oxidative coupling strategy. The overall protocol delivers conjugates in high yields and recoveries, requires a minimal excess of antibody to achieve modification of more than 95% of capsids, and can be completed in a short period of time. Antibody-capsid conjugates targeting extracellular receptors on human breast cancer cell lines were prepared and characterized. Notably, conjugation to the capsid did not significantly perturb the binding of the antibodies, as indicated by binding affinities similar to those obtained for the parent antibodies. An array of conjugates was synthesized with various reporters on the interior surface of the capsids to be used in cell studies, including fluorescence-based flow cytometry, confocal microscopy, and mass cytometry. The results of these studies lay the foundation for further exploration of these constructs in the context of clinically relevant applications, including drug delivery and in vivo diagnostics.

Synthesis, characterization and targeted cell imaging applications of poly(p-phenylene)s with amino and poly(ethylene glycol) substituents

A novel approach for bioconjugation associated with a fluorescent conjugated polymer is demonstrated.

Polymeric nano-micelles: versatile platform for targeted delivery in cancer

Polymeric micelles are among the most promising delivery systems in nanomedicine. The growing interest in polymeric micelles as drug delivery vehicle is promoted by the advantages they offer for hydrophobic anticancer agents. The size of most polymeric micelles lies within the range 10–100 nm ensuring that they can selectively leave the circulation at tumor site via the enhanced permeability and retention effect. Their unique structure allows them to solubilize hydrophobic drugs, prolongs their circulatory half-life and eventually leads to enhanced therapeutic efficacy. In addition, they can undergo several structural modifications to further augment tumor cell uptake. In this review, we will discuss various micellar systems that have been studied in preclinical and clinical settings.

Towards an electronic dog nose: surface plasmon resonance immunosensor for security and safety

This review describes an “electronic dog nose” based on a surface plasmon resonance (SPR) sensor and an antigen–antibody interaction for security and safety. We have concentrated on developing appropriate sensor surfaces for the SPR sensor for practical use. The review covers different surface fabrications, which all include variations of a self-assembled monolayer containing oligo(ethylene glycol), dendrimer, and hydrophilic polymer. We have carried out detection of explosives using the sensor surfaces. For the SPR sensor to detect explosives, the vapor or particles of the target substances have to be dissolved in a liquid. Therefore, we also review the development of sampling processes for explosives, and a protocol for the measurement of explosives on the SPR sensor in the field. Additionally, sensing elements, which have the potential to be applied for the electronic dog nose, are described.

Targeted delivery system of nanobiomaterials in anticancer therapy: from cells to clinics

Targeted delivery systems of nanobiomaterials are necessary to be developed for the diagnosis and treatment of cancer. Nanobiomaterials can be engineered to recognize cancer-specific receptors at the cellular levels and to deliver anticancer drugs into the diseased sites. In particular, nanobiomaterial-based nanocarriers, so-called nanoplatforms, are the design of the targeted delivery systems such as liposomes, polymeric nanoparticles/micelles, nanoconjugates, norganic materials, carbon-based nanobiomaterials, and bioinspired phage system, which are based on the nanosize of 1-100 nm in diameter. In this review, the design and the application of these nanoplatforms are discussed at the cellular levels as well as in the clinics. We believe that this review can offer recent advances in the targeted delivery systems of nanobiomaterials regarding in vitro and in vivo applications and the translation of nanobiomaterials to nanomedicine in anticancer therapy.