Feasibility and constraints of particle targeting using the antigen-antibody interaction

Ultrasensitive capacitance sensor to detect amyloid-beta 1-40 in human serum using supramolecular recognition of β-CD/RGO/ITO micro-disk electrode

In this paper, we developed a new ultrasensitive capacitance sensor for detection of amyloid beta 1-40 (aβ40) protein (one of Alzheimer's disease core biomarkers) in human serum based on the high supramolecular recognition of the β-cyclodextrin/reduced graphene oxide (β-CD/RGO) nanohybrid toward the anti-aβ40 antibody molecule. The sensor was established by immobilizing specific anti-aβ40 antibody onto the β-CD/RGO nanohybrid functionalized on indium tin oxide micro-disk electrode (anti-aβ40/β-CD/RGO/ITO). Detection of aβ40 in the human serum (HS) using the sensor anti-aβ40/β-CD/RGO/ITO is carried out by capacitance measurement without a redox probe to prevent protein denaturation, serving as a convenient strategy for point-of-care diagnosis. In comparison with other studies, the sensor shows a very low limit of detection of 0.69 fg mL^-1 in HS, demonstrating its ability for the ultrasensitive detection of aβ40. Using this sensor, the dissociation constant K_D of the binding interaction between anti-aβ40 and aβ40 in HS is found to be 2.9 × 10^-7 nM, indicating the high binding affinity of antibody-antigen and the suitability of the anti-aβ40/β-CD/RGO/ITO sensor for aβ40 protein detection. The good selectivity of the anti-aβ40/β-CD/RGO/ITO sensor in the presence of differential analytes was also performed in this paper.

Functionalized hydrogel microparticles prepared by microfluidics and their interaction with tumour marker carbonic anhydrase IX

Microfluidics allows precise control of the synthesis of microparticles for specific applications, where size and morphology play an important role. In this work, we have introduced microfluidic chip design with dedicated extraction and gelation sections allowing to prepare hydrogel particles in the size range of a red blood cell. The influence of the extractive channel size, alginate concentration and type of storage media on the final size of the prepared alginate microparticles has been discussed. The second part of the work is dedicated to the surface modification of prepared particles using chitosan, pHPMA and the monoclonal antibody molecule, IgG M75. The specific interaction of the antibody molecule with an antigen domain of carbonic anhydrase IX, the transmembrane tumour protein associated with several types of cancer, is demonstrated by fluorescence imaging and compared to an isotypic antibody molecule.

In Search of Advanced Tumor Diagnostics and Treatment: Achievements and Perspectives of Carbonic Anhydrase IX Targeted Delivery

The research of how cells sense and adapt the oxygen deficiency has been recognized as worth winning a Nobel Prize in 2019. Understanding hypoxia-driven molecular machinery paved a path for novel strategies in fighting hypoxia-related diseases including cancer. The oxygen depletion inside the tumor provokes HIF-1 dependent gene and protein expression which helps the tumor to survive. For this reason, tumor related molecules are in the spotlight for scientists developing anticancer agents. One such target is carbonic anhydrase IX (CA IX)-a protein located on the outer cell membrane of most hypoxic tumor cells. This offers the opportunity to exploit it as a target for delivery of cytotoxic drugs, dyes, or radioisotopes to cancer cells. Therefore, researchers investigate CA IX specific small molecules and antibodies as tumor-targeting moieties in nanosystems and conjugates which are expected to overcome the limitations of some existing diagnostic and treatment strategies. This review covers the vast majority of CA IX-targeted systems (nanoparticle and conjugate based) for both therapeutic and imaging purposes published up to now. Furthermore, it shows their stage of development and gives an assessment of their clinical translation possibilities.

Nanocomposite liposomes for pH-controlled porphyrin release into human prostate cancer cells

It is both challenging and desirable to have drug sensitizers released at acidic tumor pH for photodynamic therapy in cancer treatment. A pH-responsive carrier was prepared, in which fumed silica-attached 5,10,15,20-tetrakis(4-trimethylammoniophenyl)porphyrin (TTMAPP) was encapsulated into 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) nanocomposite liposomes. The sizes of agglomerates were determined by dynamic light scattering to be 115 nm for silica and 295 nm for silica-TTMAPP-DOPC liposomes. Morphological changes were also found in TEM images, showing liposome formation at pH 8.5 but collapse upon silanol protonation. TTMAPP release is enhanced from 13% at pH 7.5 to 80% at pH 2.3, as determined spectrophotometrically through dialysis membranes. Fluorescence emission of TTMAPP encapsulated in the dry film of liposomes was reduced to half at pH 8.6 when compared to that at pH 5.4, while the production of singlet oxygen was quintupled at pH 5.0 compared to pH 7.6. Upon treatment of human prostate cancer cells with liposomes containing 6.7 μM, 13 μM, 17 μM and 20 μM TTMAPP, the cell viabilities were determined to be 60%, 18%, 20% and 5% at pH 5.4; 58%, 30%, 25% and 10% at pH 6.3; and 90%, 82%, 68% and 35% at pH 7.4, respectively. Light-induced apoptosis in cancerous cells was only observed in the presence of liposomes at pH 6.3 and pH 5.4 but not at pH 7.4, as indicated by chromatin condensation.

Nanocomposite liposomes are relatively stable in weak basic solutions but effectively release porphyrins at acidic pH, as indicated by the difference in fluorescence.

Nanoparticles and Microfluidic Devices in Cancer Research

Cancer is considered the disease of the century, which can be easily understood considering its increasing incidence worldwide. Over the last years, nanotechnology has been presenting promising theranostic approaches to tackle cancer, as the development of nanoparticle-based therapies. But, regardless of the promising outcomes within in vitro settings, its translation into the clinics has been delayed. One of the main reasons is the lack of an appropriate in vitro model, capable to mimic the true environment of the human body, to test the designed nanoparticles. In fact, most of in vitro models used for the validation of nanoparticle-based therapies do not address adequately the complex barriers that naturally occur in a tumor scenario, as such as blood vessels, the interstitial fluid pressure or the interactions with surrounding cells that can hamper the proper delivery of the nanoparticles into the desired site. In this reasoning, to get a step closer to the in vivo reality, it has been proposed of the use of microfluidic devices. In fact, microfluidic devices can be designed on-demand to exhibit complex structures that mimic tissue/organ-level physiological architectures. Even so, despite microfluidic-based in vitro models do not compare with the reality and complexity of the human body, the most complex systems created up to now have been showing similar results to in vivo animal models. Microfluidic devices have been proven to be a valuable tool to accomplish more realistic tumour's environment. The recent advances in this field, and in particular, the ones enabling the rapid test of new therapies, and show great promise to be translated to the clinics will be overviewed herein.

Finding the perfect match between nanoparticles and microfluidics to respond to cancer challenges

The clinical translation of new cancer theranostic has been delayed by inherent cancer's heterogeneity. Additionally, this delay has been enhanced by the lack of an appropriate in vitro model, capable to produce accurate data. Nanoparticles and microfluidic devices have been used to obtain new and more efficient strategies to tackle cancer challenges. On one hand, nanoparticles-based therapeutics can be modified to target specific cells, and/or molecules, and/or modified with drugs, releasing them over time. On the other hand, microfluidic devices allow the exhibition of physiologically complex systems, incorporation of controlled flow, and control of the chemical environment. Herein, we review the use of nanoparticles and microfluidic devices to address different cancer challenges, such as detection of CTCs and biomarkers, point-of-care devices for early diagnosis and improvement of therapies. The future perspectives of cancer challenges are also addressed herein.

A Multifunctional Graphene Oxide Platform for Targeting Cancer

Diagnosis of oncological diseases remains at the forefront of current medical research. Carbonic Anhydrase IX (CA IX) is a cell surface hypoxia-inducible enzyme functionally involved in adaptation to acidosis that is expressed in aggressive tumors; hence, it can be used as a tumor biomarker. Herein, we propose a nanoscale graphene oxide (GO) platform functionalized with magnetic nanoparticles and a monoclonal antibody specific to the CA IX marker. The GO platforms were prepared by a modified Hummers and Offeman method from exfoliated graphite after several centrifugation and ultrasonication cycles. The magnetic nanoparticles were prepared by a chemical precipitation method and subsequently modified. Basic characterization of GO, such as the degree of oxidation, nanoparticle size and exfoliation, were determined by physical and chemical analysis, including X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), and atomic force microscopy (AFM). In addition, the size and properties of the poly-L-lysine-modified magnetic nanoparticles were characterized. The antibody specific to CA IX was linked via an amidic bond to the poly-L-lysine modified magnetic nanoparticles, which were conjugated to GO platform again via an amidic bond. The prepared GO-based platform with magnetic nanoparticles combined with a biosensing antibody element was used for a hypoxic cancer cell targeting study based on immunofluorescence.

Antibody-pHPMA functionalised fluorescent silica nanoparticles for colorectal carcinoma targeting

Nanoparticles functionalised with pHPMA and monoclonal antibody IgG M75 show specific adhesion to tumour cells expressing carbonic anhydrase IX bothin vitroandin vivo.

Antibody-based donor-acceptor spatial reconfiguration in decorated lanthanide-doped nanoparticle colloids for the quantification of okadaic acid biotoxin

With the increasing movement away from the mouse bioassay for the detection of toxins in commercially harvested shellfish, there is a growing demand for the development of new and potentially field-deployable tests in its place. In this direction we report the development of a simple and sensitive nanoparticle-based luminescence technique for the detection of the marine biotoxin okadaic acid. Photoluminescent lanthanide nanoparticles were conjugated with fluorophore-labelled anti-okadaic acid antibodies which, upon binding to okadaic acid, gave rise to luminescence resonance energy transfer from the nanoparticle to the organic fluorophore dye deriving from a reduction in distance between the two. The intensity ratio of the fluorophore: nanoparticle emission peaks was found to correlate with okadaic acid concentration, and the sensor showed a linear response in the 0.37-3.97 μM okadaic acid range with a limit of detection of 0.25 μM. This work may have important implications for the development of new, cheap, and versatile biosensors for a range of biomolecules and that are sufficiently simple to be applied in the field or at point-of-care.