Immobilization of cholesterol oxidase in LbL films and detection of cholesterol using ac measurements

Moraes, Marli L.; Souza, Nara C. de; Hayasaka, Caio O.; Ferreira, Marystela; Rodrigues-Filho, Ubirajara P.; Riul, Antonio; Zucolotto, Valtencir; Oliveira, Osvaldo N.

doi:10.1016/j.msec.2008.08.040

Cited by 50 publications

(38 citation statements)

References 37 publications

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“…In this context, LbL coatings offer interesting advantages such as the sole use of aqueous solutions and avoidance of organic solvents, mild formulation conditions as no temperature or physical pressure needed which are more favorable to preserve fragile protein folding and activity (Sakr & Borchard, 2013). It has been proven that entrapped water remains in LbL films, in spite of applied drying procedures, which is important for the preservation of activity of biomolecules (Moraes et al, 2009).…”

Section: Biological Activitymentioning

confidence: 99%

Sustained protein release from hydrogel microparticles using layer-by-layer (LbL) technology

2015

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Context and objectives: Since most of developed therapeutic proteins are intended to treat chronic diseases, patients are prescribed multiple injections for long time periods, and therefore, sustained release formulations are much needed. However, challenges facing these formulations are quite significant. In this context, a model protein, lysozyme (Lys), was loaded on hydrogel microparticles (beads) and the ability of layer-by-layer (LbL) coating to control Lys release and maintain its activity over a one-month period was investigated. Methods: LbL coating was composed of chondroitin sulfate as a negatively charged polyelectrolyte and a biocompatible, hydrolytically degradable poly b-aminoester as a positively charged polyelectrolyte. Loading distribution was monitored by fluorescence imaging, and followed by depositing a series of LbL coatings of different thicknesses. Release of Lys from these formulations was studied and activity of released fraction was determined. Results: Lys was loaded effectively on hydrogel beads achieving about 9 mg protein/100 mg wet spheres. LbL coating was proven successful by monitoring the zeta potential of the beads, which was reversed after the addition of each layer. In vitro release studies showed sustained release profiles that depend on the thickness of the deposited coat, with t 50 extended from 4.9 to 143.9 h. More importantly, released Lys possessed a high degree of biological activity during the course of release maintaining at least 72% of initial activity. Conclusions: Successful loading of Lys and extension of its release while maintaining a considerable degree of activity might make this formulation suitable for use with other active therapeutic proteins.

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Section: Biological Activitymentioning

confidence: 99%

Sustained protein release from hydrogel microparticles using layer-by-layer (LbL) technology

2015

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“…The p17-1 free in solution or incorporated into DPPG liposomes was immobilized in LbL films alternated with polyelectrolyte layers onto quartz substrates that had been cleaned in HCl/H 2 O 2 /H 2 O (1:1:6 (v/v)) and NH 4 OH/H 2 O 2 /H 2 O (1:1:5 (v/v)) hydrophilization solutions, both for 10 min at 80 C. 28 All solutions were prepared with pure water supplied by a Milli-Q purification system. The concentration of the polyelectrolytes was 1 mg · mL −1 , while for p17-1 the concentration was 0.25 mg · mL −1 .…”

Section: Layer-by-layer Filmmentioning

confidence: 99%

Toward Preserving the Structure of the Antigenic Peptide p17-1 from the HIV-1 p17 Protein in Nanostructured Films

Petri

Ferreira²,

Moraes³

2011

J. Nanosci. Nanotech.

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Antigenic peptides may be immobilized in nanostructured films in order to build highly specific immunosensors and other devices that require molecular recognition, with no need to use complex molecules. A major challenge for such endeavors, however, is to preserve the secondary structure of the peptides after immobilization. In this study, we show that the peptide p17-1 (LSGGELDRWEKIRLRPGG), derived from the HIV-1 p17 protein, may be immobilized in Layer-by-Layer (LbL) films made with polyelectrolytes. Its structure was preserved only if incorporated into phospholipid liposomes, according to fluorescence and circular dichroism (CD) spectroscopy. The lack of secondary structure for the peptide in the LbL film may be associated with the film-forming procedure in which p17-1 was adsorbed from an aqueous solution, where it does not form alpha helices. The importance of structure preservation was clear in the attempts to produce electrochemical immunosensors with the p17-1 peptide without being protected in liposomes in an LbL film. There was no detectable influence of the presence of anti-p17 antibodies, though some molecular interaction could be inferred from the voltammograms. In contrast, for p17-1 incorporated in liposomes electrochemical immunosensors could be obtained with the voltamogramms showing strong molecular recognition with the antibodies. These results indicated that phospholipids serve as a suitable matrix for immobilization of peptides, and confirmed the importance of structure preservation in electrochemical immunosensors.

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“…Nanobiosensors have been emerging with fast pace in the field of biomedical, agricultural and environmental sciences 138,139 and with special emphasis with layer-bylayer films [140][141][142] and with the pioneer research of Brolo and co-workers. 143 The applications in the field of detection of fatal diseases like cancer and diabetes have brought nanobiosensors in the fore front of research.…”

Section: Discussionmentioning

confidence: 99%

Biomedical applications of nanobiosensors: the state-of-the-art

Rai¹,

Gade²,

Gaikwad³

et al. 2012

J. Braz. Chem. Soc.

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O desenvolvimento de nanobiosensores é um dos avanços mais recentes no campo da nanotecnologia. A investigação sobre nanobiosensores ópticos com dimensões submicrométricas tem aberto novos horizontes para as medições intracelulares. Aproveitando as propriedades únicas dos nanomateriais, nanobiosensores mais rápidos e sensíveis podem ser desenvolvidos. Além de serem sensíveis e rápidos, os estudos de nanobiosensores têm voltado seus esforços para o desenvolvimento de sensores baseados em nanomateriais que são acessíveis, robustos e reprodutíveis. Os nanobiosensores estão equipados com sondas biorreceptoras imobilizadas, por exemplo, anticorpos, substrato de enzima. A excitação por laser é transmitida para o sistema fotométrico na forma de sinal óptico (fluorescência). Os nanobiosessores poderão revolucionar no futuro o diagnóstico de doenças. A presente revisão discute os conceitos básicos, a evolução e as aplicações biomédicas de nanobiosensores.Development of nanobiosensor is one of the most recent advancement in the field of Nanotechnology. Research on optical nanobiosensors with submicron-sized dimensions has opened new horizons for intracellular measurements. Taking advantage of the unique properties of the nanomaterials, faster and sensitive nanobiosensors can be developed. Apart from being sensitive and fast, the studies related to nanobiosensors have geared their efforts towards the development of nanomaterial-based sensors that are affordable, robust and reproducible. The nanobiosensors are equipped with immobilized bioreceptor probes, e.g., antibodies, enzyme substrate. Laser excitation is transmitted to photometric system in the form of optical signal (fluorescence). Nanobiosensors will revolutionize the future of disease diagnosis. The present review discusses the basic concepts, developments and the biomedical applications of nanobiosensors.

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Immobilization of cholesterol oxidase in LbL films and detection of cholesterol using ac measurements

Cited by 50 publications

References 37 publications

Sustained protein release from hydrogel microparticles using layer-by-layer (LbL) technology

Sustained protein release from hydrogel microparticles using layer-by-layer (LbL) technology

Toward Preserving the Structure of the Antigenic Peptide p17-1 from the HIV-1 p17 Protein in Nanostructured Films

Biomedical applications of nanobiosensors: the state-of-the-art

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