Biomedical Platform Research Articles

Immunological Properties of Protein-Polymer Nanoparticles.

The covalent attachment of polymers to the surface of proteins and nanoparticles has been widely employed in the development of biomedical platforms capable of delaying or diminishing immune surveillance. The most widely employed polymer for these applications has been poly(ethylene glycol) (PEG), yet recent evidence has suggested that other polymer architectures and compositions provide significantly better in vitro and in vivo properties of protein-polymer hybrid materials. Moreover, few direct comparisons of PEG to these polymers have been reported. Here we describe the assembly and characterization of a series of polymer conjugates of a representative immunogenic viruslike particle (VLP) using (poly(oligo(ethylene glycol) methacrylate), poly(methacrylamido glucopyranose), and PEG, and an investigation of their ability to shield the protein from antibody recognition as a function of polymer loading density, chain length, architecture, and conjugation site. Increasing chain length and loading density were both found to significantly diminish antibody recognition of the VLP conjugates; the conformation adopted by different polymer architectures was also found to greatly influence antibody recognition. A direct comparison of these conjugates to PEGylated VLPs in vivo showed that all formulations gave rise to similar antibody titers that were significantly diminished relative to unmodified particles. Interestingly, the quality of the antibody response was impacted by the properties of the conjugate, with differences in observed affinity and avidity suggesting a complex dependence on loading density, chain length, and architecture.

Biomedical Platform Development of a Chlorophyll-Based Extract for Topic Photodynamic Therapy: Mechanical and Spectroscopic Properties.

RETURN TO ISSUEPREVAddition/CorrectionNEXTORIGINAL ARTICLEThis notice is a correctionBiomedical Platform Development of a Chlorophyll-Based Extract for Topic Photodynamic Therapy: Mechanical and Spectroscopic PropertiesKatieli da S. S. Campanholi*Katieli da S. S. CampanholiMore by Katieli da S. S. Campanholihttp://orcid.org/0000-0001-5156-8542, Gustavo BragaGustavo BragaMore by Gustavo Braga, Jéssica B. da SilvaJéssica B. da SilvaMore by Jéssica B. da Silva, Nicola L. da RochaNicola L. da RochaMore by Nicola L. da Rocha, Lizziane M. B. de FranciscoLizziane M. B. de FranciscoMore by Lizziane M. B. de Francisco, Évelin L. de OliveiraÉvelin L. de OliveiraMore by Évelin L. de Oliveira, Marcos L. BruschiMarcos L. BruschiMore by Marcos L. Bruschi, Lidiane V. de Castro-HoshinoLidiane V. de Castro-HoshinoMore by Lidiane V. de Castro-Hoshino, Francielle SatoFrancielle SatoMore by Francielle Sato, Noboru HiokaNoboru HiokaMore by Noboru Hioka, and Wilker CaetanoWilker CaetanoMore by Wilker CaetanoCite this: Langmuir 2018, 34, 43, 13077Publication Date (Web):October 18, 2018Publication History Published online18 October 2018Published inissue 30 October 2018https://doi.org/10.1021/acs.langmuir.8b02961Copyright © 2018 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views366Altmetric-Citations1LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (181 KB) Get e-Alerts Get e-Alerts

Genotyping of Multiple Clinical Samples with a Combined Direct PCR and Magnetic Lateral Flow Assay

SummaryDeveloping a sensitive, low-cost, and easy-to-use point-of-care testing system for genotyping is important for informing treatment decisions and predicting the risk of underlying diseases. Conventional methods normally require complex operational procedures as well as expensive and sophisticated instruments. Here, we report a general approach that enables us to detect the genotype of multiple sample types directly without DNA purification. Moreover, the PCR results can be further quantitatively analyzed based on a magnetic lateral flow assay (MLFA) system, which avoids multiple steps needed for conventional nucleic acid biosensors. As a demonstration, we show that three genotypes of aldehyde dehydrogenase 2 (ALDH2) can be identified using a small volume of sample with an accuracy of 100% and a sensitivity of 1.0 × 102 cells/μL, which are better than those of the gold standard methods. We believe that the direct PCR-MLFA system represents a significant advance toward the development of portable, sensitive biomedical platforms.

Magnetic responsive cell-based strategies for diagnostics and therapeutics

The potential of magnetically assisted strategies within the remit of cell-based therapies is increasing, creating new opportunities for biomedical platforms and in the field of tissue engineering and regenerative medicine. Among the magnetic elements approached for building magnetically responsive strategies, superparamagnetic iron oxide nanoparticles (SPIONs) represent tunable and precise tools whose properties can be modelled for detection, diagnosis, targeting and therapy purposes. The most investigated clinical role of SPIONs is as contrast imaging agents for tracking and monitoring cells and tissues. Nevertheless, magnetic detection also includes biomarker mapping, cell labelling and cell/drug targeting to monitor cell events and anticipate the disruption of homeostatic conditions and the progression of disease. Additionally, the isolation and screening techniques of cell subsets in heterogeneous populations or of proteins of interest have been explored in a magnetic sorting context. More recently, SPION-based technologies have been applied to stimulate cell differentiation and mechanotransduction processes and to transport genetic or drug cargo to study biological mechanisms and contribute to improved therapies. Magnetically based strategies significantly contribute to magnetic tissue engineering (magTE), in which magnetically responsive actuators built from magnetic labelled cells or magnetic functionalized systems can be remotely controlled and spatially manipulated upon the actuation of an external magnetic field for the delivery or target of TE solutions. SPION functionalities combined with magnetic responsiveness in multifactorial magnetically assisted platforms can revolutionize diagnosis and therapeutics, providing new diagnosis and theranostic tools, encouraging regenerative medicine approaches and having potential for more effective therapies. This review will address the contribution of SPION-based technologies as multifunctional tools in boosting magnetically assisted cell-based strategies to explore diagnostics and tracking solutions for the detection and analysis of pathologies, and to generate improved treatments and therapies, envisioning precise and customized answers for the management of numerous diseases.

Perspective: Magnetoresistive sensors for biomedicine

Currently, there is a plethora of sensors (e.g., electrochemical, optical, and piezoelectric) used in life sciences for either analyte detection or diagnostic purposes, but in the last decade, magnetic biosensors have received extended interest as a promising candidate for the development of next-generation, highly sensitive biomedical platforms. This approach is based on magnetic labeling, replacing the otherwise classic fluorescence labeling, combined with magnetic sensors that detect the stray field of the superparamagnetic markers (e.g., magnetic micro-nanoparticles or magnetic nanostructures). Apart from the increased sensitivity, magnetic biosensors exhibit the unique ability of controlling and modulating the superparamagnetic markers by an externally applied magnetic force as well as the capability of compact integration of their electronics on a single chip. The magnetic field sensing mechanism most widely investigated for applications in life sciences is based on the magnetoresistance (MR) effect that was first discovered in 1856 by Lord Kelvin. However, it is the giant magnetoresistance effect, discovered by Grünberg and Fert in 1988, that actually exhibits the greatest potential as a biosensing principle. This perspective will shortly explain the magnetic labeling method and will provide a brief overview of the different MR sensor technologies (giant magnetoresistive, spin valves, and tunnel magnetoresistive) mostly used in biosensing applications as well as a compact assessment of the state of the art. Newly implemented innovations and their broad-ranging implications will be discussed, challenges that need to be addressed will be identified, and new hypotheses will be proposed.

A Review on the Extraction of Quantitative Retinal Microvascular Image Feature.

Digital image processing is one of the most widely used computer vision technologies in biomedical engineering. In the present modern ophthalmological practice, biomarkers analysis through digital fundus image processing analysis greatly contributes to vision science. This further facilitates developments in medical imaging, enabling this robust technology to attain extensive scopes in biomedical engineering platform. Various diagnostic techniques are used to analyze retinal microvasculature image to enable geometric features measurements such as vessel tortuosity, branching angles, branching coefficient, vessel diameter, and fractal dimension. These extracted markers or characterized fundus digital image features provide insights and relates quantitative retinal vascular topography abnormalities to various pathologies such as diabetic retinopathy, macular degeneration, hypertensive retinopathy, transient ischemic attack, neovascular glaucoma, and cardiovascular diseases. Apart from that, this noninvasive research tool is automated, allowing it to be used in large-scale screening programs, and all are described in this present review paper. This paper will also review recent research on the image processing-based extraction techniques of the quantitative retinal microvascular feature. It mainly focuses on features associated with the early symptom of transient ischemic attack or sharp stroke.

Biomedical Platform Development of a Chlorophyll-Based Extract for Topic Photodynamic Therapy: Mechanical and Spectroscopic Properties.

Photodynamic therapy (PDT) is a therapeutic modality that has shown effectiveness in the inactivation of cancer cell lines and microorganisms. Treatment consists of activating the photosensitizer (PS) upon light irradiation of adequate wavelength. After reaching the excited state, the PS can handle the intersystem conversion through energy transfer to the molecular oxygen, generating reactive oxygen species. This especially applies to singlet oxygen (1O2), which is responsible for the selective destruction of the sick tissue. Photosensitizing compounds (chlorophylls and derivatives) existing in the spinach extract have applicability for PDT. This study aimed to develop and characterize the thermoresponsive bioadhesive system composed of Pluronic F127 20.0%- and Carbopol 934P 0.2% (w/w) (FC)-containing chlorophyll-based extract 0.5% (w/w) (FC-Chl). Mechanical and rheological properties, in vitro release, sol-gel transition temperature, and ex vivo permeability of the spinach extract PS components (through pig ear skin) were investigated. Furthermore, photodynamic activity of the system was accessed through uric acid and time-solved measurements. The sol-gel transition temperature obtained for the FC-Chl system was 28.8 ± 0.3 °C. Rheological and texture properties of the platform were suitable for use as a dermatological system, exhibiting easy application and good characteristics of retention in the place of administration. In vitro release studies showed the presence of two distinct mechanisms that reasonably obey the zero-order and first-order kinetics models. PS components presented skin permeability and reached a permeation depth of 830 μm (between the epidermis and dermis). The photodynamic evaluation of the FC-Chl system was effective in the degradation of uric acid. The quantum yield (ΦΔ1O2) and life time (τ1O2) of singlet oxygen showed similar values for the spinach extract and the isolated chlorophyll a species in ethanol. These results allowed for the classification of the FC-Chl platform as potentially useful for the delivery of the chlorophyll-based extract in the topic PDT, suggesting that it is worthy for in vivo evaluation.

Hyperpolarized Porous Silicon Nanoparticles: Potential Theragnostic Material for 29 Si Magnetic Resonance Imaging.

Porous silicon nanoparticles have recently garnered attention as potentially-promising biomedical platforms for drug delivery and medical diagnostics. Here, we demonstrate porous silicon nanoparticles as contrast agents for 29 Si magnetic resonance imaging. Size-controlled porous silicon nanoparticles were synthesized by magnesiothermic reduction of silica nanoparticles and were surface activated for further functionalization. Particles were hyperpolarized via dynamic nuclear polarization to enhance their 29 Si MR signals; the particles demonstrated long 29 Si spin-lattice relaxation (T1 ) times (∼25 mins), which suggests potential applicability for medical imaging. Furthermore, 29 Si hyperpolarization levels were sufficient to allow 29 Si MRI in phantoms. These results underscore the potential of porous silicon nanoparticles that, when combined with hyperpolarized magnetic resonance imaging, can be a powerful theragnostic deep tissue imaging platform to interrogate various biomolecular processes in vivo.

Digital Technology: The Future Is Bright

Digital Technology: The Future Is Bright

Two-step relaxation process of colloidal magnetic nanoclusters under pulsed fields

We empirically uncovered a two-step process of a temporal magnetization response under a pulsed field, which was observed by delaying the particle kinetics in a viscous medium. The Brownian alignment of the magnetization easy-axis appeared to occur separately after the rotated moments reached equilibrium, instead of randomly mixed relaxation behavior. The effective cluster moment and anisotropic magnetopotential difference are two key factors for determining each contribution to the steady-state magnetization. This finding adds new insight to the understanding of colloidal magnetic nanoclusters as a semi-rigid dipole system, which has potential applications in biomedical platforms.

Recent Advances in Laser-Ablative Synthesis of Bare Au and Si Nanoparticles and Assessment of Their Prospects for Tissue Engineering Applications.

Driven by surface cleanness and unique physical, optical and chemical properties, bare (ligand-free) laser-synthesized nanoparticles (NPs) are now in the focus of interest as promising materials for the development of advanced biomedical platforms related to biosensing, bioimaging and therapeutic drug delivery. We recently achieved significant progress in the synthesis of bare gold (Au) and silicon (Si) NPs and their testing in biomedical tasks, including cancer imaging and therapy, biofuel cells, etc. We also showed that these nanomaterials can be excellent candidates for tissue engineering applications. This review is aimed at the description of our recent progress in laser synthesis of bare Si and Au NPs and their testing as functional modules (additives) in innovative scaffold platforms intended for tissue engineering tasks.

New progression and direction of translational medicine on colorectal cancer

Translational medicine is characterized by its close association with precision medicine in the field of colo-rectal cancer. In particular, the studies of life histology promote the prevention and treatment of colorectal cancer entered the stage of precision medicine. Accurate molecular typing of colo-rectal cancer has been used to guide clinical practice is an important breakthrough in the field of colorectal cancer translational medicine in recent years, and its clinical value has been verified. As an important tool for the effective integration of clinical data and life histology data, the biomedical big data platform is expected to contribute to the continued breakthrough of translational medicine in precision molecular typing. New treatment methods, such as liquid biopsy technology with non-invasive, flexible features can be dynamically detected as soon as possible to find the state of somatic mutations. Among them, circulating tumor DNA has a good detection sensitivity and specificity, highlighting the value of early recurrence monitoring. In addition, new therapeutic strategies, such as immunological checkpoints and chimeric antigen receptor genetically modified T-cell therapy, are under intense study in the field of colorectal cancer. Based on the biomedical big data analysis in the context of the precise molecular typing, dynamic liquid biopsy monitoring technology, new immunotherapy and other fields will be the future of colorectal cancer translational medicine research hot and breakthrough direction. Key words: Colorectal neoplasms; Translational medicine; Precision medicine; Mole-cular subtyping; Big data; Liquid biopsy technology; Immunologic therapy

Translocation of Engineered Nanomaterials from the Maternal Lungs to the Fetal Compartment After Instillation

The majority of exposures to engineered nanomaterials (ENM) are unintentional through occupational or domestic use; however ENM biomedical platforms are being developed for use in individualized and/or tissue‐targeted treatments. The placenta has been described as a barrier organ, yet maternal treatments are limited during pregnancy to diminish untoward fetal effects and direct fetal therapies are rare. While negative maternal and fetal effects have been described after ENM exposure during gestation, it is unclear if these are due to direct ENM transfer into the fetal compartment or if the placental barrier protects the fetus from direct particle exposure. Therefore, the purpose of this study was to identify ENM translocation after maternal pulmonary exposure to the fetal compartment.Sprague‐Dawley rats were exposed to 2974 μg (2.4 × 1013 particles; calculated deposition of 952 ug/dose) of Rhodamine‐labeled 20nm polystyrene (NANOCS) in 300μL or saline control via intratracheal instillation every other day from GD 5 to GD 19. An acute group was also included, with a single ENM exposure on GD19. Animals were exposed to many optical imaging techniques (CT, FX‐Pro optical imaging, and ultrasound), in either the whole animal or dissected tissues on GD 20. Litter health was affected as evidenced by significantly higher rates of reabsorption sites in the exposed dams (18‐fold, chronic; 7‐fold, acute) compared to control. Overall, we were able to identify significantly higher optical intensity measurements in many secondary organs of the exposed animals, indicative of particle translocation from the lung. These included significantly increased optical imaging intensities in the chronic group vs the controls in the placenta (142% ± 78), whole fetal pup (144% ± 17), and in situ fetal liver (146% ± 13). Interestingly even those acutely exposed (24h prior) were also significantly different than control. These were identified as the mother's heart (156% ± 8), spleen (158% ± 6), placenta (142% ± 78), fetal heart (177% ± 37), fetal liver (both excised (190% ± 14) and within body (164% ± 10)), and whole pup (157% ± 13). Using novel placental perfusion methodology, where a placental unit is isolated, dissected, cannulated and perfused (80 mmHg maternal artery and 50 mmHg fetal umbilical artery), ENM introduced in the maternal artery can be quantified within 102 ± 13 minutes from the fetal umbilical vein effluent.Using molecular imaging techniques, we were able to conclusively identify ENM translocation from the maternal lungs to the fetal compartment. These findings may be both beneficial and toxicological depending on the purpose of the ENM exposure. ENM transfer to the fetal compartment may allow for direct fetal treatment with the use of ENM‐based biomedical devices; in contrast the placenta may not be considered a barrier to ENM, with direct fetal contact also occurring after unintentional maternal ENM exposures.Support or Funding InformationNIH‐R00‐ES024783 (PAS); P30‐ES005022This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Modulating Swimming Behaviors in Wildtype and Cannabinoid Receptors (CB1 & CB2) Mutant Zebrafish Larvae

Discovery of new psychiatric drugs has been painfully slow, while diagnosed psychiatric disorders have risen, creating an urgent need for novel approaches bolstering this domain. A major drawback is that promising drugs, found by classic approaches like in vitro/in silico systems or neuronal cells, will have to be tested for safety and efficacy in a complex organism. Rodents are usually the preferred model because of an advanced understanding of the central nervous system (CNS) function and the availability of well‐accepted behavioral tests. However, ethical considerations and prohibitive costs do not allow rapid multiple dosages testing of a high number of animals to account for the inherent variability of candidate drugs that get overseen. We propose to use zebrafish larvae as an intermediate model. This lower vertebrate offers the possibility to perform up‐scalable behavioral screens in a genetic tractable model and has been successfully used for drug safety and discovery. It is particularly suited to further assess the genetic contribution to a pharmacological response which can give insight into the drug's mode of action, but also assert its safety in genetics variants. As prove of principle, we focused on a well‐known neuronal signaling pathway: the endocannabinoid system (eCBs), which is mediated via two cannabinoid receptors 1 and 2 (CB1 and CB2, encoded by cnr1 and cnr2 genes respectively). The classical view of CB1 acting in the CNS and CB2 in the peripheral immune system has been recently challenged by mounting evidence revealing that CB2 is also expressed in the CNS and some CB2‐dependent neuromodulation. To investigate further their role as neuromodulators and how the receptors work alone or in combination, we generated CB1 and CB2 loss‐of‐function mutations using CRISPR/Cas9. Wild type and mutant larvae, lacking one or both CBs, were recorded in a photo‐dependent swimming response assay (PDR). We focused on well‐accepted anxiety‐like parameters: hypo/hyper‐activity, center avoidance, and photo‐stimulated startle response. Next, we evaluated larvae’ PDR performance in presence of different neurotropic compounds. We chose a well‐described anxiogenic drug Pentylenetetrazole, Diphenhydramine (main component of Benadryl®) which has a narcotic effect, and copper, a commonly found water contaminant known to induce anxiety‐like behaviors. We found that PDR alterations were clearly genotyped and compound specific, therefore demonstrating the eCBs signaling role in those anxiety‐like behaviors. Furthermore, it is also proving that our composite approach is a quantifiable read‐out for drug efficacy. This work lays the foundations for biomedical platforms to screen neurotropic molecules in variable genetic context to reinforce drug discovery. In addition, it can be extended to dissect neuronal signaling pathway(s) by systematic use of loss‐of‐function mutations in genes relevant for understanding altered‐behaviors lined to neuropsychiatric disorders.Support or Funding InformationR25 GM061838, MBRS‐Research Initiative for Scientific Enhancement (RISE) Program/NSF‐CREST (#HRD‐1137725)‐Puerto Rico Center of Environmental Neuroscience (PRCEN)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Front Cover: A theoretical‐experimental methodology for assessing the sensitivity of biomedical spectral imaging platforms, assays, and analysis methods (J. Biophotonics 1/2018)

A hyperspectral image data cube acquired from HEK‐293 cells labeled with cytoplasmic and nuclear stains: Calcein Green and NucBlu. The top view (XY plane) displays three spectrally unmixed channels for cellular autofluorescence (red), Calcein Green (green), and NucBlue (blue). The Z axis shows spectral information, from low to high wavelength. The article by Leavesley and colleagues describes an approach for calculating the sensitivity of spectral imaging assays for detecting a fluorescence signature within a mix of other signatures or autofluorescence. Further details can be found in the article by Silas J. Leavesley et al. (e201600227). image

Rapid and Sensitive Genotyping of Multiple Clinical Samples Based on a Combined Direct PCR and Magnetic Lateral Flow Assay

Developing a sensitive, low cost and easy-to-use point-of-care testing system for genotyping is important for informing treatment decisions and predicting the risk of underlying diseases. Conventional methods normally require complex operational procedures as well as expensive and sophisticated instruments. Here, we report a general approach that enables us to detect the genotype of multiple sample types directly without DNA purification Moreover, the PCR results can be further quantitatively analyzed based on a magnetic lateral flow assay (MLFA) system, which avoids multiple steps needed for conventional nucleic acid biosensors. As a demonstration, we show that three genotypes of aldehyde dehydrogenase 2 (ALDH2) can be identified using a small volume of sample with an accuracy of 100% and a sensitivity of 1.0×102 cells/μL, which are better than those of the gold standard methods. We believe the direct PCR-MLFA system represents a significant advance towards the development of portable, sensitive biomedical platforms.

The Central Role of Wnt Signaling and Organoid Technology in Personalizing Anticancer Therapy.

The Wnt pathway is at the heart of organoid technology, which is set to revolutionize the cancer field. We can now predetermine a patient's response to any given anticancer therapy by exposing tumor organoids established from the patient's own tumor. This cutting-edge biomedical platform translates to patients being treated with the correct drug at the correct dose from the outset, a truly personalized and precise medical approach. A high throughput drug screen on organoids also allows drugs to be tested in limitless combinations. More recently, the tumor cells that are resistant to the therapy given to a patient were selected in culture using the patient's organoids. The resistant tumor organoids were then screened empirically to identify drugs that will kill the resistant cells. This information allows diagnosis in real-time to either prevent tumor recurrence or effectively treat the recurring tumor. Furthermore, the ability to culture stem cell-derived epithelium as organoids has enabled us to begin to understand how a stem cell becomes a cancer cell or to pin-point the genetic alteration that underlies a given genetic syndrome. Here we summarize these advances and the central role of Wnt signaling, and identify the next challenges for organoid technology.

Ascidian‐Inspired Fast‐Forming Hydrogel System for Versatile Biomedical Applications: Pyrogallol Chemistry for Dual Modes of Crosslinking Mechanism

AbstractExploitation of unique biochemical and biophysical properties of marine organisms has led to the development of functional biomaterials for various biomedical applications. Recently, ascidians have received great attention, owing to their extraordinary properties such as strong underwater adhesion and rapid self‐regeneration. Specific polypeptides containing 3,4,5‐trihydroxyphenylalanine (TOPA) in the blood cells of ascidians are associated with such intrinsic properties generated through complex oxidative processes. In this study, a bioinspired hydrogel platform is developed, demonstrating versatile applicability for tissue engineering and drug delivery, by conjugating pyrogallol (PG) moiety resembling ascidian TOPA to hyaluronic acid (HA). The HA–PG conjugate can be rapidly crosslinked by dual modes of oxidative mechanisms using an oxidant or pH control, resulting in hydrogels with different mechanical and physical characteristics. The versatile utility of HA–PG hydrogels formed via different crosslinking mechanisms is tested for different biomedical platforms, including microparticles for sustained drug delivery and tissue adhesive for noninvasive cell transplantation. With extraordinarily fast and different routes of PG oxidation, ascidian‐inspired HA–PG hydrogel system may provide a promising biomaterial platform for a wide range of biomedical applications.

Targeting breast cancer cells with a CuInS2/ZnS quantum dot-labeled Ki-67 bioprobe.

The aim of the present study was to develop a water-soluble biomarker for the detection of breast cancer using quantum dots (QDs) conjugated to Ki-67, a nuclear protein associated with the cell cycle. Ki-67 is also a marker of cell proliferation, with expression levels categorizing good and poor prognosis in invasive breast cancer. Ki-67 is a clinically used biomarker for breast cancer diagnosis, treatment and prognosis. Owing to the optical and chemical advantages of QDs, QD-based nanotechnology may aid the construction of a biomedical imaging platform for the study of cancer cell behavior. In the present study, a biomarker was prepared by employing the water-soluble CuInS2/ZnS QDs conjugated to an anti-Ki-67 monoclonal antibody to detect Ki-67 expression in breast cancer. The QDs, which were hydrophobic and coated with octadecylamine, were encapsulated with an amphiphilic biocompatible centipede-like polymer, and then conjugated to anti-Ki-67 monoclonal antibodies (QD-Ki-67 probes). The QD-Ki-67 probes retained the original optical properties of the unadorned QDs and did not exhibit distinct toxic side effects in in vitro cytotoxicity experiments. Therefore, this CuInS2/ZnS QD-labeled bioprobe, with a high quantum yield and low cytotoxicity, is a promising candidate for bioimaging and may be used as a cell label.

Enhanced pattern resolution, swelling-behaviour and biocompatibility of bioimprinted casein microdevices

This work introduces casein microstructures with surface features as a biodegradable biomedical platform technology for enhancing tissue-engineering applications. An optimized fabrication process is presented to reduce the hydrophobicity of intermediate polydimethylsiloxane (PDMS) molds and to transfer high-resolution regular and biomimetic features onto the surface of casein devices. Four different cross-linking reagents, glutaraldehyde, formaldehyde, citric acid and transglutaminase (TG) were investigated to increase the degradation time of casein and their influence on swelling and biocompatibility of the films was studied. TG was found to be the only cross-linker to effectively increase the degradation time and show reduced film swelling after immersion into media, while remaining compatible with cell-culture. The maximum expansion of the films cross-linked via TG was 33% after 24 hours of immersion in cell-culture media. C2C12 cells were successfully cultured on the patterned films for up to 72 hours. The patterned biodegradable casein substrates presented here have promising applications in stem-cell engineering, regenerative medicine, and implantable devices.