The development of solid materials that deliver nitric oxide (NO) are of interest for several therapeutic applications. Nevertheless, due to NO’s reactive nature, rapid diffusion and short half-life, reporting their NO delivery characteristics is rather complex. The full knowledge of this parameter is fundamental to discuss the therapeutic utility of these materials, and thus, the NO quantification strategy must be carefully considered according to the NO-releasing scaffold type, to the expected NO-releasing amounts and to the medium of quantification. In this work, we explore and discuss three different ways of quantifying the release of NO in different biological fluids: haemoglobin assay, Griess assay and NO electrochemical detection. For these measurements, different porous materials, namely zeolites and titanosilicates were used as models for NO-releasing platforms. The oxyhaemoglobin assay offers great sensitivity (nanomolar levels), but it is only possible to monitor the NO release while oxyhaemoglobin is not fully converted. On the other hand, Griess assay has low sensitivity in complex biological media, namely in blood, and interferences with media make NO measurements questionable. Nevertheless, this method can measure micromolar amounts of NO and may be useful for an initial screening for long-term release performance. The electrochemical sensor enabled real-time measurements in a variety of biological settings. However, measured NO is critically low in oxygenated and complex media, giving transient signals, which makes long-term quantification impossible. Despite the disadvantages of each method, the combination of all the results provided a more comprehensive NO release profile for these materials, which will help to determine which formulations are most promising for specific therapeutic applications. This study highlights the importance of using appropriate NO quantification tools to provide accurate reports.

Gas therapy using gasotransmitters is of exponential interest due to the growing recognition of gas signaling molecules that can be involved in multiple therapeutic actions. Finding suitable methods for delivering these molecules is crucial, and porous materials, notably metal‐organic frameworks (MOFs), have shown exceptional potential as gas carriers, enabling safe and controlled local delivery. The challenges to translate these MOF therapies to clinical use require not only to validate the mechanisms of action and signaling pathways for the released gas molecules but also get a deep understanding into the MOF rational design, as it requires a combination of features to maximize the therapeutic outcomes. In this perspective, we outline the key criteria for designing suitable MOFs for gas delivery applications and highlight the expanding range of therapeutic opportunities these materials may offer. Readers can use these insights of MOF design and features to develop gasotransmitter therapies with realistic clinic interest.