Retention of Activity by Antibodies Immobilized on Gold Nanoparticles of Different Sizes: Fluorometric Method of Determination and Comparative Evaluation

Antibody–nanoparticle conjugates are widely used analytical reagents. An informative parameter reflecting the conjugates’ properties is the number of antibodies per nanoparticle that retain their antigen-binding ability. Estimation of this parameter is characterized by a lack of simple, reproducible methods. The proposed method is based on the registration of fluorescence of tryptophan residues contained in proteins and combines sequential measurements of first the immobilized antibody number and then the bound protein antigen number. Requirements for the measurement procedure have been determined to ensure reliable and accurate results. Using the developed technique, preparations of spherical gold nanoparticles obtained by the most common method of citrate reduction of gold salts (the Turkevich–Frens method) and varying in average diameter from 15 to 55 nm have been characterized. It was shown that the number of antibodies (immunoglobulins G) bound by one nanoparticle ranged from 30 to 194 during adsorptive unoriented monolayer immobilization. C-reactive protein was considered as the model antigen. The percentage of antibody valences that retained their antigen-binding properties in the conjugate increased from 17 to 34% with an increase in the diameter of gold nanoparticles. The proposed method and the results of the study provide tools to assess the capabilities of the preparations of gold nanoparticles and their conjugates as well as the expediency of seeking the best techniques for various practical purposes.

60 cases of pulmonary tuberculosis treated with gold salts Dumarest, Lebeuf (Pr. Med. 1932, no. 62)

Dumarest, Lebeuf were injected intramuscularly 2-3 times a week at a dose of 0.1-0.2 gold Solganel preparation to patients with various forms of pulmonary TB and received anatomical changes with a recovery of 23%, improvement with incomplete anatomy.

Enzyme mediated synthesis of hybrid polyedric gold nanoparticles

Large protein complexes carry out some of the most complex activities in biology1,2. Such structures are often assembled spontaneously through the process of self-assembly and have characteristic chemical or biological assets in the cellular mechanisms3. Gold-based nanomaterials have attracted much attention in many areas of chemistry, physics and biosciences because of their size- and shape-dependent optic, electric, and catalytic properties. Here we report for the first time a one step synthesis in which Manganese Superoxide Dismutase protein plays a key role in the reduction of gold salts via the use of a Good's buffer (HEPES) to produce gold nanoparticles, compared to other proteins as catalase (CAT) and bovine serum albumin (BSA).We prove that this effect is directly related with the biological activities of the proteins that have an effect on the gold reduction mechanisms. Such synthesis route also induces the integration of proteins directly in the AuNPs that are intrinsically safe by design using a one-step production method. This is an important finding that will have uses in various applications, particularly in the green synthesis of novel nanomaterials.

Gold-based therapy: From past to present

Despite an abundant literature on gold nanoparticles use for biomedicine, only a few of the gold-based nanodevices are currently tested in clinical trials, and none of them are approved by health agencies. Conversely, ionic gold has been used for decades to treat human rheumatoid arthritis and benefits from 70-y hindsight on medical use. With a view to open up new perspectives in gold nanoparticles research and medical use, we revisit here the literature on therapeutic gold salts. We first summarize the literature on gold salt pharmacokinetics, therapeutic effects, adverse reactions, and the present repurposing of these ancient drugs. Owing to these readings, we evidence the existence of a common metabolism of gold nanoparticles and gold ions and propose to use gold salts as a “shortcut” to assess the long-term effects of gold nanoparticles, such as their fate and toxicity, which remain challenging questions nowadays. Moreover, one of gold salts side effects (i.e., a blue discoloration of the skin exposed to light) leads us to propose a strategy to biosynthesize large gold nanoparticles from gold salts using light irradiation. These hypotheses, which will be further investigated in the near future, open up new avenues in the field of ionic gold and gold nanoparticles-based therapies.

Diazonium Gold Salts as Novel Surface Modifiers: What Have We Learned So Far?

The challenges of diazonium salts stabilization have been overcome by their isolation as metal salts such as tetrachloroaurate(III). The cleavage of molecular nitrogen from diazonium salts even at very low potential or on reducing surfaces by fine tuning the substituents on the phenyl ring expanded their applications as surface modifiers in forensic science, nanomedicine engineering, catalysis and energy. The robustness of the metal–carbon bonding produced from diazonium salts reduction has already opened an era for further applications. The integration of experimental and calculations in this field catalyzed its speedy progress. This review provides a narrative of the progress in this chemistry with stress on our recent contribution, identifies potential applications, and highlights the needs in this emerging field. For these reasons, we hope that this review paper serves as motivation for others to enter this developing field of surface modification originating from diazonium salts.

Mechanistic insights of the reduction of gold salts in the Turkevich protocol

The Turkevich protocol consists of two consecutive reduction steps (Au3+ → Au+ → Au0) rather than a reduction followed by the disproportionation reaction as conventionally believed. The second reduction is the rate-limiting step.

Azathioprine-Induced Severe Bone Marrow Suppression

Aplastic anemia is characterized by bone marrow failure and pancytopenia. It could be due to autoimmune disorders, radiation, drugs, or chemicals. Drugs that mostly cause aplastic anemia include chloramphenicol, non-steroidal anti-inflammatory drugs, antiepileptic drugs, gold salts, and antithyroid drugs. Clinical sign and symptoms often result from pancytopenia that includes signs of anemia and bleeding. In some patients, fever and sepsis are seen that are due to neutropenia. Azathioprine is a purine antimetabolite, an immunosuppressive drug that causes myelosuppression and pancytopenia, especially in patients who have some degrees of TPMT (Thiopurine Methyltransferase) activity. We present a patient who admitted to our hospital with fever and pancytopenia and a history of recent azathioprine treatment. Because of delay in the recovery of pancytopenia, she was suspected of aplastic anemia, and bone marrow aspiration and biopsy were done for her.

Rheumatoid nodules in the lung parenchyma in rheumatoid arthritis

Rheumatoid nodules (RNs) are one of the most common extra-articular manifestations of rheumatoid arthritis (RA), but are rarely located in lung tissue. The development of extra-articular (systemic) manifestations of RA is associated with the high levels of rheumatoid factor and anticyclic citrullinated peptide antibodies. The specific features of the course of RNs in lung tissue are their frequent occurrence with minimally pronounced joint inflammatory changes or remission. In rare cases, RNs are prone to disintegration and suppuration, which may be complicated by the formation of small caverns, hemoptysis, and, if located subpleurally, pneumothorax. In addition, there are publications on the possible relationship of the formation of RNs and their accelerated development to the administration of immunosuppressive drugs (methotrexate, tocilizumab, D-penicillamine, gold salts, leflunomide, infliximab, and other TNF-α inhibitors) and on the association of pulmonary RNs with methotrexate treatment. The paper describes a clinical case of a female patient with RA-systemic sclerosis overlap syndrome and RN formation in lung tissue early at disease onset when the DAS28 target level for RA has been achieved. The atypical outline of a pulmonary nodule has required a differential diagnostic search. The results of imaging RNs in the lung and their dynamics are shown. The given data are discussed.

Plantar Psoriasis Associated with Olmesartan

Background: Psoriasis is a chronic inflammatory skin disorder that may be initiated or exacerbated by some drug intakes. Some of the most common medications known to trigger or worsen existing psoriasis include lithium, gold salts, beta blockers and antimalarials. Conclusion: We report an exceptional case of plantar psoriasis in a woman who was treated by olmesartan for 3 years.

Photochemical preparation of gold nanoparticle decorated cyclodextrin vesicles with tailored plasmonic properties

Plasmonic vesicles are obtained by in situ photochemical reduction of gold salts at the vesicle surface using a stabilizing photoactive polymer shell that generates reducing ketyl radicals upon irradiation.